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Dynamic memory allocation for channel lock in USB driver #102

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ddv2005 opened this issue Sep 4, 2012 · 7 comments
Closed

Dynamic memory allocation for channel lock in USB driver #102

ddv2005 opened this issue Sep 4, 2012 · 7 comments

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@ddv2005
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ddv2005 commented Sep 4, 2012

Hi,

Latest USB driver use dynamic allocation for channel lock inside a functions. I guess that is waste a time because it can be easily allocated only once.

https://gist.github.com/3625562

Dmitry

@popcornmix
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Does it improve iperf numbers? (or any other performance measures)

@ddv2005
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ddv2005 commented Sep 5, 2012

I didn't test but it should because theoretically it eliminate 500-16000 memory allocations per second.

@popcornmix
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I tested it and couldn't see an improvement in iperf. However I agree it is more efficient, so I've committed it.
Thanks.

@ghollingworth
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Dmitry,

Can you test the kernel containing the fix and close the issue when you're happy?

@ddv2005
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ddv2005 commented Sep 9, 2012

I tested and it is good. Thanks.

P.S. But I am still can't be happy because USB audio is still terrible and I can't find the problem without hardware USB protocol analyzer :-(.

@ddv2005 ddv2005 closed this as completed Sep 9, 2012
@ghollingworth
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The problem is the same as almost all the other USB problems, in that
it isn't able to keep up properly because of poor interrupt latency in
the Linux kernel...

We're trying to get somewhere on this

Gordon

On 09/09/2012, Dmitry Dudkin notifications@github.com wrote:

I tested and it is good. Thanks.

P.S. But I am still can't be happy because USB audio is still terrible and I
can't find the problem without hardware USB protocol analyzer :-(.


Reply to this email directly or view it on GitHub:
#102 (comment)

Sent from my mobile device

@ddv2005
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ddv2005 commented Sep 9, 2012

I am not sure. Now I have 3 problems with USB audio:

  1. Clock drift (recording thread capture 200-3000 samples per second more that playback thread)
  2. Clicking sound when USB audio device connected directly to Raspberry PI. (even with Y USB cable for external power)
  3. Sometimes SSPLIT OUT transaction is failed (when device connected to external MultiTT hub) that cause reset the device.

I found that in DEBUG mode I never seen a clock drift. Deep investigation shown that if I put small delay (1-10 usec) for split transactions at end of dwc_otg_hc_start_transfer then it fix problem with clock drift even under the load. I guess that this delay prevent reordering several (playback & capture) start split transactions.
But I sill have problems #2 & #3 and no way to found the problem without hardware USB protocol analyzer. Because something wrong with split transactions and only way to found it - capture USB traffic and see what is wrong.

P.S. Do you have access to Synposys documentation for USB controller? I would be very appreciate if somebody sent me this documentation. I tried contact to Synposys but still no response.

popcornmix pushed a commit that referenced this issue Jan 22, 2014
These mappings are in fact special and require special handling in privcmd,
which already exists. Failure to mark the PTE as special on arm64 causes all
sorts of bad PTE fun. e.g.

e.g.:

BUG: Bad page map in process xl  pte:e0004077b33f53 pmd:4079575003
page:ffffffbce1a2f328 count:1 mapcount:-1 mapping:          (null) index:0x0
page flags: 0x4000000000000014(referenced|dirty)
addr:0000007fb5259000 vm_flags:040644fa anon_vma:          (null) mapping:ffffffc03a6fda58 index:0
vma->vm_ops->fault: privcmd_fault+0x0/0x38
vma->vm_file->f_op->mmap: privcmd_mmap+0x0/0x2c
CPU: 0 PID: 2657 Comm: xl Not tainted 3.12.0+ #102
Call trace:
[<ffffffc0000880f8>] dump_backtrace+0x0/0x12c
[<ffffffc000088238>] show_stack+0x14/0x1c
[<ffffffc0004b67e0>] dump_stack+0x70/0x90
[<ffffffc000125690>] print_bad_pte+0x12c/0x1bc
[<ffffffc0001268f4>] unmap_single_vma+0x4cc/0x700
[<ffffffc0001273b4>] unmap_vmas+0x68/0xb4
[<ffffffc00012c050>] unmap_region+0xcc/0x1d4
[<ffffffc00012df20>] do_munmap+0x218/0x314
[<ffffffc00012e060>] vm_munmap+0x44/0x64
[<ffffffc00012ed78>] SyS_munmap+0x24/0x34

Where unmap_single_vma contains inlined -> unmap_page_range -> zap_pud_range
-> zap_pmd_range -> zap_pte_range -> print_bad_pte.

Or:

BUG: Bad page state in process xl  pfn:4077b4d
page:ffffffbce1a2f8d8 count:0 mapcount:-1 mapping:          (null) index:0x0
page flags: 0x4000000000000014(referenced|dirty)
Modules linked in:
CPU: 0 PID: 2657 Comm: xl Tainted: G    B        3.12.0+ #102
Call trace:
[<ffffffc0000880f8>] dump_backtrace+0x0/0x12c
[<ffffffc000088238>] show_stack+0x14/0x1c
[<ffffffc0004b67e0>] dump_stack+0x70/0x90
[<ffffffc00010f798>] bad_page+0xc4/0x110
[<ffffffc00010f8b4>] free_pages_prepare+0xd0/0xd8
[<ffffffc000110e94>] free_hot_cold_page+0x28/0x178
[<ffffffc000111460>] free_hot_cold_page_list+0x38/0x60
[<ffffffc000114cf0>] release_pages+0x190/0x1dc
[<ffffffc00012c0e0>] unmap_region+0x15c/0x1d4
[<ffffffc00012df20>] do_munmap+0x218/0x314
[<ffffffc00012e060>] vm_munmap+0x44/0x64
[<ffffffc00012ed78>] SyS_munmap+0x24/0x34

x86 already gets this correct. 32-bit arm gets away with this because there is
not PTE_SPECIAL bit in the PTE there and the vm_normal_page fallback path does
the right thing.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
popcornmix pushed a commit that referenced this issue Jun 8, 2014
During the EEH hotplug event, iommu_add_device() will be invoked three times
and two of them will trigger warning or error.

The three times to invoke the iommu_add_device() are:

    pci_device_add
       ...
       set_iommu_table_base_and_group   <- 1st time, fail
    device_add
       ...
       tce_iommu_bus_notifier           <- 2nd time, succees
    pcibios_add_pci_devices
       ...
       pcibios_setup_bus_devices        <- 3rd time, re-attach

The first time fails, since the dev->kobj->sd is not initialized. The
dev->kobj->sd is initialized in device_add().
The third time's warning is triggered by the re-attach of the iommu_group.

After applying this patch, the error

    iommu_tce: 0003:05:00.0 has not been added, ret=-14

and the warning

    [  204.123609] ------------[ cut here ]------------
    [  204.123645] WARNING: at arch/powerpc/kernel/iommu.c:1125
    [  204.123680] Modules linked in: xt_CHECKSUM nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT bnep bluetooth 6lowpan_iphc rfkill xt_conntrack ebtable_nat ebtable_broute bridge stp llc mlx4_ib ib_sa ib_mad ib_core ib_addr ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw bnx2x tg3 mlx4_core nfsd ptp mdio ses libcrc32c nfs_acl enclosure be2net pps_core shpchp lockd kvm uinput sunrpc binfmt_misc lpfc scsi_transport_fc ipr scsi_tgt
    [  204.124356] CPU: 18 PID: 650 Comm: eehd Not tainted 3.14.0-rc5yw+ #102
    [  204.124400] task: c0000027ed485670 ti: c0000027ed50c000 task.ti: c0000027ed50c000
    [  204.124453] NIP: c00000000003cf80 LR: c00000000006c648 CTR: c00000000006c5c0
    [  204.124506] REGS: c0000027ed50f440 TRAP: 0700   Not tainted  (3.14.0-rc5yw+)
    [  204.124558] MSR: 9000000000029032 <SF,HV,EE,ME,IR,DR,RI>  CR: 88008084  XER: 20000000
    [  204.124682] CFAR: c00000000006c644 SOFTE: 1
    GPR00: c00000000006c648 c0000027ed50f6c0 c000000001398380 c0000027ec260300
    GPR04: c0000027ea92c000 c00000000006ad00 c0000000016e41b0 0000000000000110
    GPR08: c0000000012cd4c0 0000000000000001 c0000027ec2602ff 0000000000000062
    GPR12: 0000000028008084 c00000000fdca200 c0000000000d1d90 c0000027ec281a80
    GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
    GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000001
    GPR24: 000000005342697b 0000000000002906 c000001fe6ac9800 c000001fe6ac9800
    GPR28: 0000000000000000 c0000000016e3a80 c0000027ea92c090 c0000027ea92c000
    [  204.125353] NIP [c00000000003cf80] .iommu_add_device+0x30/0x1f0
    [  204.125399] LR [c00000000006c648] .pnv_pci_ioda_dma_dev_setup+0x88/0xb0
    [  204.125443] Call Trace:
    [  204.125464] [c0000027ed50f6c0] [c0000027ed50f750] 0xc0000027ed50f750 (unreliable)
    [  204.125526] [c0000027ed50f750] [c00000000006c648] .pnv_pci_ioda_dma_dev_setup+0x88/0xb0
    [  204.125588] [c0000027ed50f7d0] [c000000000069cc8] .pnv_pci_dma_dev_setup+0x78/0x340
    [  204.125650] [c0000027ed50f870] [c000000000044408] .pcibios_setup_device+0x88/0x2f0
    [  204.125712] [c0000027ed50f940] [c000000000046040] .pcibios_setup_bus_devices+0x60/0xd0
    [  204.125774] [c0000027ed50f9c0] [c000000000043acc] .pcibios_add_pci_devices+0xdc/0x1c0
    [  204.125837] [c0000027ed50fa50] [c00000000086f970] .eeh_reset_device+0x36c/0x4f0
    [  204.125939] [c0000027ed50fb20] [c00000000003a2d8] .eeh_handle_normal_event+0x448/0x480
    [  204.126068] [c0000027ed50fbc0] [c00000000003a35c] .eeh_handle_event+0x4c/0x340
    [  204.126192] [c0000027ed50fc80] [c00000000003a74c] .eeh_event_handler+0xfc/0x1b0
    [  204.126319] [c0000027ed50fd30] [c0000000000d1ea0] .kthread+0x110/0x130
    [  204.126430] [c0000027ed50fe30] [c00000000000a460] .ret_from_kernel_thread+0x5c/0x7c
    [  204.126556] Instruction dump:
    [  204.126610] 7c0802a6 fba1ffe8 fbc1fff0 fbe1fff8 f8010010 f821ff71 7c7e1b78 60000000
    [  204.126787] 60000000 e87e0298 3143ffff 7d2a1910 <0b090000> 2fa90000 40de00c8 ebfe0218
    [  204.126966] ---[ end trace 6e7aefd80add2973 ]---

are cleared.

This patch removes iommu_add_device() in pnv_pci_ioda_dma_dev_setup(), which
revert part of the change in commit d905c5d(PPC: POWERNV: move
iommu_add_device earlier).

Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
anholt referenced this issue in anholt/linux Apr 14, 2016
This patch fixes a typo in khugepaged_scan_pmd(): instead of setting
"result" to SCAN_EXCEED_SWAP_PTE we set "ret". Setting "ret" results in
an attempt to collapse a huge page although we meant aborting the scan.
As a result, we can call khugepaged_find_target_node() with all entries
in the khugepaged_node_load array being zeros. The latter is not ready
for that and might return an offline node on such input. This leads to a
warning followed by kernel panic:

  WARNING: CPU: 1 PID: 40 at include/linux/gfp.h:314 khugepaged_alloc_page+0xd4/0xf0()
  CPU: 1 PID: 40 Comm: khugepaged Not tainted 4.3.0-rc1-mm1+ #102
   000000000000013a ffff88010ae77b58 ffffffff813270d4 ffffffff818cda31
   0000000000000000 ffff88010ae77b98 ffffffff8107c9f5 dead000000000100
   ffff88010ae77e70 0000000000c752da 0000000000000001 0000000000000000
  Call Trace:
   [<ffffffff813270d4>] dump_stack+0x48/0x64
   [<ffffffff8107c9f5>] warn_slowpath_common+0x95/0xe0
   [<ffffffff8107ca5a>] warn_slowpath_null+0x1a/0x20
   [<ffffffff811ec124>] khugepaged_alloc_page+0xd4/0xf0
   [<ffffffff811f15c8>] collapse_huge_page+0x58/0x550
   [<ffffffff810b38e6>] ? account_entity_dequeue+0xb6/0xd0
   [<ffffffff810b5289>] ? idle_balance+0x79/0x2b0
   [<ffffffff811f1f5e>] khugepaged_scan_pmd+0x49e/0x710
   [<ffffffff810e1f3a>] ? lock_timer_base+0x5a/0x80
   [<ffffffff810e1fbb>] ? try_to_del_timer_sync+0x5b/0x70
   [<ffffffff810e214c>] ? del_timer_sync+0x4c/0x60
   [<ffffffff8168242f>] ? schedule_timeout+0x11f/0x200
   [<ffffffff811f2330>] khugepaged_scan_mm_slot+0x160/0x2a0
   [<ffffffff811f255f>] khugepaged_do_scan+0xef/0x160
   [<ffffffff810bcdb0>] ? wait_woken+0x80/0x80
   [<ffffffff811f25d0>] ? khugepaged_do_scan+0x160/0x160
   [<ffffffff811f25f8>] khugepaged+0x28/0x80
   [<ffffffff8109ab1c>] kthread+0xcc/0xf0
   [<ffffffff810a667e>] ? schedule_tail+0x1e/0xc0
   [<ffffffff8109aa50>] ? kthread_freezable_should_stop+0x70/0x70
   [<ffffffff8168371f>] ret_from_fork+0x3f/0x70
   [<ffffffff8109aa50>] ? kthread_freezable_should_stop+0x70/0x70

  BUG: unable to handle kernel paging request at 0000000000014028
  IP: [<ffffffff81185eb2>] __alloc_pages_nodemask+0xc2/0x2c0
  PGD aaac7067 PUD aaac606 PMD 0
  Oops: 0000 [#1] SMP
  CPU: 1 PID: 40 Comm: khugepaged Tainted: G        W       4.3.0-rc1-mm1+ #102
  task: ffff88010ae16400 ti: ffff88010ae74000 task.ti: ffff88010ae74000
  RIP: 0010:[<ffffffff81185eb2>]  [<ffffffff81185eb2>] __alloc_pages_nodemask+0xc2/0x2c0
  RSP: 0018:ffff88010ae77ad8  EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 0000000000014020 RCX: 0000000000000014
  RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000c752da
  RBP: ffff88010ae77ba8 R08: 0000000000000000 R09: 0000000000000001
  R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000
  R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000c752da
  FS:  0000000000000000(0000) GS:ffff88010be40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000014028 CR3: 00000000aaac4000 CR4: 00000000000006e0
  Stack:
   ffff88010ae77ae8 ffffffff810d0b3b ffff88010ae77b48 ffffffff81179e73
   0000000000000010 ffff88010ae77b58 ffff88010ae77b18 ffffffff811ec124
   ffff88010ae77b38 00000009a6e3aff4 0000000000000000 0000000000000000
  Call Trace:
   [<ffffffff810d0b3b>] ? vprintk_default+0x2b/0x40
   [<ffffffff81179e73>] ? printk+0x46/0x48
   [<ffffffff811ec124>] ? khugepaged_alloc_page+0xd4/0xf0
   [<ffffffff8107ca04>] ? warn_slowpath_common+0xa4/0xe0
   [<ffffffff811ec0cd>] khugepaged_alloc_page+0x7d/0xf0
   [<ffffffff811f15c8>] collapse_huge_page+0x58/0x550
   [<ffffffff810b38e6>] ? account_entity_dequeue+0xb6/0xd0
   [<ffffffff810b5289>] ? idle_balance+0x79/0x2b0
   [<ffffffff811f1f5e>] khugepaged_scan_pmd+0x49e/0x710
   [<ffffffff810e1f3a>] ? lock_timer_base+0x5a/0x80
   [<ffffffff810e1fbb>] ? try_to_del_timer_sync+0x5b/0x70
   [<ffffffff810e214c>] ? del_timer_sync+0x4c/0x60
   [<ffffffff8168242f>] ? schedule_timeout+0x11f/0x200
   [<ffffffff811f2330>] khugepaged_scan_mm_slot+0x160/0x2a0
   [<ffffffff811f255f>] khugepaged_do_scan+0xef/0x160
   [<ffffffff810bcdb0>] ? wait_woken+0x80/0x80
   [<ffffffff811f25d0>] ? khugepaged_do_scan+0x160/0x160
   [<ffffffff811f25f8>] khugepaged+0x28/0x80
   [<ffffffff8109ab1c>] kthread+0xcc/0xf0
   [<ffffffff810a667e>] ? schedule_tail+0x1e/0xc0
   [<ffffffff8109aa50>] ? kthread_freezable_should_stop+0x70/0x70
   [<ffffffff8168371f>] ret_from_fork+0x3f/0x70
   [<ffffffff8109aa50>] ? kthread_freezable_should_stop+0x70/0x70
  RIP  [<ffffffff81185eb2>] __alloc_pages_nodemask+0xc2/0x2c0
   RSP <ffff88010ae77ad8>
  CR2: 0000000000014028

Fixes: acc067d59a1f9 ("mm: make optimistic check for swapin readahead")
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
anholt referenced this issue in anholt/linux May 31, 2016
This patch fixes a typo in khugepaged_scan_pmd(): instead of setting
"result" to SCAN_EXCEED_SWAP_PTE we set "ret". Setting "ret" results in
an attempt to collapse a huge page although we meant aborting the scan.
As a result, we can call khugepaged_find_target_node() with all entries
in the khugepaged_node_load array being zeros. The latter is not ready
for that and might return an offline node on such input. This leads to a
warning followed by kernel panic:

  WARNING: CPU: 1 PID: 40 at include/linux/gfp.h:314 khugepaged_alloc_page+0xd4/0xf0()
  CPU: 1 PID: 40 Comm: khugepaged Not tainted 4.3.0-rc1-mm1+ #102
   000000000000013a ffff88010ae77b58 ffffffff813270d4 ffffffff818cda31
   0000000000000000 ffff88010ae77b98 ffffffff8107c9f5 dead000000000100
   ffff88010ae77e70 0000000000c752da 0000000000000001 0000000000000000
  Call Trace:
   [<ffffffff813270d4>] dump_stack+0x48/0x64
   [<ffffffff8107c9f5>] warn_slowpath_common+0x95/0xe0
   [<ffffffff8107ca5a>] warn_slowpath_null+0x1a/0x20
   [<ffffffff811ec124>] khugepaged_alloc_page+0xd4/0xf0
   [<ffffffff811f15c8>] collapse_huge_page+0x58/0x550
   [<ffffffff810b38e6>] ? account_entity_dequeue+0xb6/0xd0
   [<ffffffff810b5289>] ? idle_balance+0x79/0x2b0
   [<ffffffff811f1f5e>] khugepaged_scan_pmd+0x49e/0x710
   [<ffffffff810e1f3a>] ? lock_timer_base+0x5a/0x80
   [<ffffffff810e1fbb>] ? try_to_del_timer_sync+0x5b/0x70
   [<ffffffff810e214c>] ? del_timer_sync+0x4c/0x60
   [<ffffffff8168242f>] ? schedule_timeout+0x11f/0x200
   [<ffffffff811f2330>] khugepaged_scan_mm_slot+0x160/0x2a0
   [<ffffffff811f255f>] khugepaged_do_scan+0xef/0x160
   [<ffffffff810bcdb0>] ? wait_woken+0x80/0x80
   [<ffffffff811f25d0>] ? khugepaged_do_scan+0x160/0x160
   [<ffffffff811f25f8>] khugepaged+0x28/0x80
   [<ffffffff8109ab1c>] kthread+0xcc/0xf0
   [<ffffffff810a667e>] ? schedule_tail+0x1e/0xc0
   [<ffffffff8109aa50>] ? kthread_freezable_should_stop+0x70/0x70
   [<ffffffff8168371f>] ret_from_fork+0x3f/0x70
   [<ffffffff8109aa50>] ? kthread_freezable_should_stop+0x70/0x70

  BUG: unable to handle kernel paging request at 0000000000014028
  IP: [<ffffffff81185eb2>] __alloc_pages_nodemask+0xc2/0x2c0
  PGD aaac7067 PUD aaac606 PMD 0
  Oops: 0000 [#1] SMP
  CPU: 1 PID: 40 Comm: khugepaged Tainted: G        W       4.3.0-rc1-mm1+ #102
  task: ffff88010ae16400 ti: ffff88010ae74000 task.ti: ffff88010ae74000
  RIP: 0010:[<ffffffff81185eb2>]  [<ffffffff81185eb2>] __alloc_pages_nodemask+0xc2/0x2c0
  RSP: 0018:ffff88010ae77ad8  EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 0000000000014020 RCX: 0000000000000014
  RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000c752da
  RBP: ffff88010ae77ba8 R08: 0000000000000000 R09: 0000000000000001
  R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000
  R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000c752da
  FS:  0000000000000000(0000) GS:ffff88010be40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000014028 CR3: 00000000aaac4000 CR4: 00000000000006e0
  Stack:
   ffff88010ae77ae8 ffffffff810d0b3b ffff88010ae77b48 ffffffff81179e73
   0000000000000010 ffff88010ae77b58 ffff88010ae77b18 ffffffff811ec124
   ffff88010ae77b38 00000009a6e3aff4 0000000000000000 0000000000000000
  Call Trace:
   [<ffffffff810d0b3b>] ? vprintk_default+0x2b/0x40
   [<ffffffff81179e73>] ? printk+0x46/0x48
   [<ffffffff811ec124>] ? khugepaged_alloc_page+0xd4/0xf0
   [<ffffffff8107ca04>] ? warn_slowpath_common+0xa4/0xe0
   [<ffffffff811ec0cd>] khugepaged_alloc_page+0x7d/0xf0
   [<ffffffff811f15c8>] collapse_huge_page+0x58/0x550
   [<ffffffff810b38e6>] ? account_entity_dequeue+0xb6/0xd0
   [<ffffffff810b5289>] ? idle_balance+0x79/0x2b0
   [<ffffffff811f1f5e>] khugepaged_scan_pmd+0x49e/0x710
   [<ffffffff810e1f3a>] ? lock_timer_base+0x5a/0x80
   [<ffffffff810e1fbb>] ? try_to_del_timer_sync+0x5b/0x70
   [<ffffffff810e214c>] ? del_timer_sync+0x4c/0x60
   [<ffffffff8168242f>] ? schedule_timeout+0x11f/0x200
   [<ffffffff811f2330>] khugepaged_scan_mm_slot+0x160/0x2a0
   [<ffffffff811f255f>] khugepaged_do_scan+0xef/0x160
   [<ffffffff810bcdb0>] ? wait_woken+0x80/0x80
   [<ffffffff811f25d0>] ? khugepaged_do_scan+0x160/0x160
   [<ffffffff811f25f8>] khugepaged+0x28/0x80
   [<ffffffff8109ab1c>] kthread+0xcc/0xf0
   [<ffffffff810a667e>] ? schedule_tail+0x1e/0xc0
   [<ffffffff8109aa50>] ? kthread_freezable_should_stop+0x70/0x70
   [<ffffffff8168371f>] ret_from_fork+0x3f/0x70
   [<ffffffff8109aa50>] ? kthread_freezable_should_stop+0x70/0x70
  RIP  [<ffffffff81185eb2>] __alloc_pages_nodemask+0xc2/0x2c0
   RSP <ffff88010ae77ad8>
  CR2: 0000000000014028

Fixes: acc067d59a1f9 ("mm: make optimistic check for swapin readahead")
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
popcornmix pushed a commit that referenced this issue Jun 10, 2019
commit 5cdb0ef upstream.

In case USB disconnect happens at the moment transmitting workqueue is in
progress the underlying interface may be gone causing a NULL pointer
dereference. Add synchronization of the workqueue destruction with the
detach implementation in core so that the transmitting workqueue is stopped
during detach before the interfaces are removed.

Fix following Oops:

Unable to handle kernel NULL pointer dereference at virtual address 00000008
pgd = 9e6a802d
[00000008] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in: nf_log_ipv4 nf_log_common xt_LOG xt_limit iptable_mangle
xt_connmark xt_tcpudp xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
iptable_filter ip_tables x_tables usb_f_mass_storage usb_f_rndis u_ether
usb_serial_simple usbserial cdc_acm brcmfmac brcmutil smsc95xx usbnet
ci_hdrc_imx ci_hdrc ulpi usbmisc_imx 8250_exar 8250_pci 8250 8250_base
libcomposite configfs udc_core
CPU: 0 PID: 7 Comm: kworker/u8:0 Not tainted 4.19.23-00076-g03740aa-dirty #102
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Workqueue: brcmf_fws_wq brcmf_fws_dequeue_worker [brcmfmac]
PC is at brcmf_txfinalize+0x34/0x90 [brcmfmac]
LR is at brcmf_fws_dequeue_worker+0x218/0x33c [brcmfmac]
pc : [<7f0dee64>]    lr : [<7f0e4140>]    psr: 60010093
sp : ee8abef0  ip : 00000000  fp : edf38000
r10: ffffffed  r9 : edf38970  r8 : edf3800
r7 : edf3e970  r6 : 00000000  r5 : ede69000  r4 : 00000000
r3 : 00000a97  r2 : 00000000  r1 : 0000888e  r0 : ede69000
Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 10c5387d  Table: 7d03c04a  DAC: 00000051
Process kworker/u8:0 (pid: 7, stack limit = 0x24ec3e04)
Stack: (0xee8abef0 to 0xee8ac000)
bee0:                                     ede69000 00000000 ed56c3e0 7f0e4140
bf00: 00000001 00000000 edf3800 edf3e99c ed56c3e0 80d03d00 edfea43a edf3e970
bf20: ee809880 ee804200 ee971100 00000000 edf3e974 00000000 ee804200 80135a70
bf40: 80d03d00 ee804218 ee809880 ee809894 ee804200 80d03d00 ee804218 ee8aa000
bf60: 00000088 80135d5c 00000000 ee829f00 ee829dc0 00000000 ee809880 80135d30
bf80: ee829f1c ee873eac 00000000 8013b1a0 ee829dc0 8013b07c 00000000 00000000
bfa0: 00000000 00000000 00000000 801010e8 00000000 00000000 00000000 00000000
bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[<7f0dee64>] (brcmf_txfinalize [brcmfmac]) from [<7f0e4140>] (brcmf_fws_dequeue_worker+0x218/0x33c [brcmfmac])
[<7f0e4140>] (brcmf_fws_dequeue_worker [brcmfmac]) from [<80135a70>] (process_one_work+0x138/0x3f8)
[<80135a70>] (process_one_work) from [<80135d5c>] (worker_thread+0x2c/0x554)
[<80135d5c>] (worker_thread) from [<8013b1a0>] (kthread+0x124/0x154)
[<8013b1a0>] (kthread) from [<801010e8>] (ret_from_fork+0x14/0x2c)
Exception stack(0xee8abfb0 to 0xee8abff8)
bfa0:                                     00000000 00000000 00000000 00000000
bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
Code: e1530001 0a000007 e3560000 e1a00005 (05942008)
---[ end trace 079239dd31c86e90 ]---

Signed-off-by: Piotr Figiel <p.figiel@camlintechnologies.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
popcornmix pushed a commit that referenced this issue Jun 10, 2019
commit 5cdb0ef upstream.

In case USB disconnect happens at the moment transmitting workqueue is in
progress the underlying interface may be gone causing a NULL pointer
dereference. Add synchronization of the workqueue destruction with the
detach implementation in core so that the transmitting workqueue is stopped
during detach before the interfaces are removed.

Fix following Oops:

Unable to handle kernel NULL pointer dereference at virtual address 00000008
pgd = 9e6a802d
[00000008] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in: nf_log_ipv4 nf_log_common xt_LOG xt_limit iptable_mangle
xt_connmark xt_tcpudp xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
iptable_filter ip_tables x_tables usb_f_mass_storage usb_f_rndis u_ether
usb_serial_simple usbserial cdc_acm brcmfmac brcmutil smsc95xx usbnet
ci_hdrc_imx ci_hdrc ulpi usbmisc_imx 8250_exar 8250_pci 8250 8250_base
libcomposite configfs udc_core
CPU: 0 PID: 7 Comm: kworker/u8:0 Not tainted 4.19.23-00076-g03740aa-dirty #102
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Workqueue: brcmf_fws_wq brcmf_fws_dequeue_worker [brcmfmac]
PC is at brcmf_txfinalize+0x34/0x90 [brcmfmac]
LR is at brcmf_fws_dequeue_worker+0x218/0x33c [brcmfmac]
pc : [<7f0dee64>]    lr : [<7f0e4140>]    psr: 60010093
sp : ee8abef0  ip : 00000000  fp : edf38000
r10: ffffffed  r9 : edf38970  r8 : edf3800
r7 : edf3e970  r6 : 00000000  r5 : ede69000  r4 : 00000000
r3 : 00000a97  r2 : 00000000  r1 : 0000888e  r0 : ede69000
Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 10c5387d  Table: 7d03c04a  DAC: 00000051
Process kworker/u8:0 (pid: 7, stack limit = 0x24ec3e04)
Stack: (0xee8abef0 to 0xee8ac000)
bee0:                                     ede69000 00000000 ed56c3e0 7f0e4140
bf00: 00000001 00000000 edf3800 edf3e99c ed56c3e0 80d03d00 edfea43a edf3e970
bf20: ee809880 ee804200 ee971100 00000000 edf3e974 00000000 ee804200 80135a70
bf40: 80d03d00 ee804218 ee809880 ee809894 ee804200 80d03d00 ee804218 ee8aa000
bf60: 00000088 80135d5c 00000000 ee829f00 ee829dc0 00000000 ee809880 80135d30
bf80: ee829f1c ee873eac 00000000 8013b1a0 ee829dc0 8013b07c 00000000 00000000
bfa0: 00000000 00000000 00000000 801010e8 00000000 00000000 00000000 00000000
bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[<7f0dee64>] (brcmf_txfinalize [brcmfmac]) from [<7f0e4140>] (brcmf_fws_dequeue_worker+0x218/0x33c [brcmfmac])
[<7f0e4140>] (brcmf_fws_dequeue_worker [brcmfmac]) from [<80135a70>] (process_one_work+0x138/0x3f8)
[<80135a70>] (process_one_work) from [<80135d5c>] (worker_thread+0x2c/0x554)
[<80135d5c>] (worker_thread) from [<8013b1a0>] (kthread+0x124/0x154)
[<8013b1a0>] (kthread) from [<801010e8>] (ret_from_fork+0x14/0x2c)
Exception stack(0xee8abfb0 to 0xee8abff8)
bfa0:                                     00000000 00000000 00000000 00000000
bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
Code: e1530001 0a000007 e3560000 e1a00005 (05942008)
---[ end trace 079239dd31c86e90 ]---

Signed-off-by: Piotr Figiel <p.figiel@camlintechnologies.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
popcornmix pushed a commit that referenced this issue Nov 3, 2020
I got the following lockdep splat with tree locks converted to rwsem
patches on btrfs/104:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.9.0+ #102 Not tainted
  ------------------------------------------------------
  btrfs-cleaner/903 is trying to acquire lock:
  ffff8e7fab6ffe30 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x32/0x170

  but task is already holding lock:
  ffff8e7fab628a88 (&fs_info->commit_root_sem){++++}-{3:3}, at: btrfs_find_all_roots+0x41/0x80

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (&fs_info->commit_root_sem){++++}-{3:3}:
	 down_read+0x40/0x130
	 caching_thread+0x53/0x5a0
	 btrfs_work_helper+0xfa/0x520
	 process_one_work+0x238/0x540
	 worker_thread+0x55/0x3c0
	 kthread+0x13a/0x150
	 ret_from_fork+0x1f/0x30

  -> #2 (&caching_ctl->mutex){+.+.}-{3:3}:
	 __mutex_lock+0x7e/0x7b0
	 btrfs_cache_block_group+0x1e0/0x510
	 find_free_extent+0xb6e/0x12f0
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb1/0x330
	 alloc_tree_block_no_bg_flush+0x4f/0x60
	 __btrfs_cow_block+0x11d/0x580
	 btrfs_cow_block+0x10c/0x220
	 commit_cowonly_roots+0x47/0x2e0
	 btrfs_commit_transaction+0x595/0xbd0
	 sync_filesystem+0x74/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x36/0xa0
	 cleanup_mnt+0x12d/0x190
	 task_work_run+0x5c/0xa0
	 exit_to_user_mode_prepare+0x1df/0x200
	 syscall_exit_to_user_mode+0x54/0x280
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&space_info->groups_sem){++++}-{3:3}:
	 down_read+0x40/0x130
	 find_free_extent+0x2ed/0x12f0
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb1/0x330
	 alloc_tree_block_no_bg_flush+0x4f/0x60
	 __btrfs_cow_block+0x11d/0x580
	 btrfs_cow_block+0x10c/0x220
	 commit_cowonly_roots+0x47/0x2e0
	 btrfs_commit_transaction+0x595/0xbd0
	 sync_filesystem+0x74/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x36/0xa0
	 cleanup_mnt+0x12d/0x190
	 task_work_run+0x5c/0xa0
	 exit_to_user_mode_prepare+0x1df/0x200
	 syscall_exit_to_user_mode+0x54/0x280
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (btrfs-root-00){++++}-{3:3}:
	 __lock_acquire+0x1167/0x2150
	 lock_acquire+0xb9/0x3d0
	 down_read_nested+0x43/0x130
	 __btrfs_tree_read_lock+0x32/0x170
	 __btrfs_read_lock_root_node+0x3a/0x50
	 btrfs_search_slot+0x614/0x9d0
	 btrfs_find_root+0x35/0x1b0
	 btrfs_read_tree_root+0x61/0x120
	 btrfs_get_root_ref+0x14b/0x600
	 find_parent_nodes+0x3e6/0x1b30
	 btrfs_find_all_roots_safe+0xb4/0x130
	 btrfs_find_all_roots+0x60/0x80
	 btrfs_qgroup_trace_extent_post+0x27/0x40
	 btrfs_add_delayed_data_ref+0x3fd/0x460
	 btrfs_free_extent+0x42/0x100
	 __btrfs_mod_ref+0x1d7/0x2f0
	 walk_up_proc+0x11c/0x400
	 walk_up_tree+0xf0/0x180
	 btrfs_drop_snapshot+0x1c7/0x780
	 btrfs_clean_one_deleted_snapshot+0xfb/0x110
	 cleaner_kthread+0xd4/0x140
	 kthread+0x13a/0x150
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

  Chain exists of:
    btrfs-root-00 --> &caching_ctl->mutex --> &fs_info->commit_root_sem

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_info->commit_root_sem);
				 lock(&caching_ctl->mutex);
				 lock(&fs_info->commit_root_sem);
    lock(btrfs-root-00);

   *** DEADLOCK ***

  3 locks held by btrfs-cleaner/903:
   #0: ffff8e7fab628838 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: cleaner_kthread+0x6e/0x140
   #1: ffff8e7faadac640 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x40b/0x5c0
   #2: ffff8e7fab628a88 (&fs_info->commit_root_sem){++++}-{3:3}, at: btrfs_find_all_roots+0x41/0x80

  stack backtrace:
  CPU: 0 PID: 903 Comm: btrfs-cleaner Not tainted 5.9.0+ #102
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:
   dump_stack+0x8b/0xb0
   check_noncircular+0xcf/0xf0
   __lock_acquire+0x1167/0x2150
   ? __bfs+0x42/0x210
   lock_acquire+0xb9/0x3d0
   ? __btrfs_tree_read_lock+0x32/0x170
   down_read_nested+0x43/0x130
   ? __btrfs_tree_read_lock+0x32/0x170
   __btrfs_tree_read_lock+0x32/0x170
   __btrfs_read_lock_root_node+0x3a/0x50
   btrfs_search_slot+0x614/0x9d0
   ? find_held_lock+0x2b/0x80
   btrfs_find_root+0x35/0x1b0
   ? do_raw_spin_unlock+0x4b/0xa0
   btrfs_read_tree_root+0x61/0x120
   btrfs_get_root_ref+0x14b/0x600
   find_parent_nodes+0x3e6/0x1b30
   btrfs_find_all_roots_safe+0xb4/0x130
   btrfs_find_all_roots+0x60/0x80
   btrfs_qgroup_trace_extent_post+0x27/0x40
   btrfs_add_delayed_data_ref+0x3fd/0x460
   btrfs_free_extent+0x42/0x100
   __btrfs_mod_ref+0x1d7/0x2f0
   walk_up_proc+0x11c/0x400
   walk_up_tree+0xf0/0x180
   btrfs_drop_snapshot+0x1c7/0x780
   ? btrfs_clean_one_deleted_snapshot+0x73/0x110
   btrfs_clean_one_deleted_snapshot+0xfb/0x110
   cleaner_kthread+0xd4/0x140
   ? btrfs_alloc_root+0x50/0x50
   kthread+0x13a/0x150
   ? kthread_create_worker_on_cpu+0x40/0x40
   ret_from_fork+0x1f/0x30
  BTRFS info (device sdb): disk space caching is enabled
  BTRFS info (device sdb): has skinny extents

This happens because qgroups does a backref lookup when we create a
delayed ref.  From here it may have to look up a root from an indirect
ref, which does a normal lookup on the tree_root, which takes the read
lock on the tree_root nodes.

To fix this we need to add a variant for looking up roots that searches
the commit root of the tree_root.  Then when we do the backref search
using the commit root we are sure to not take any locks on the tree_root
nodes.  This gets rid of the lockdep splat when running btrfs/104.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
popcornmix pushed a commit that referenced this issue Nov 17, 2020
[ Upstream commit 49d11be ]

I got the following lockdep splat with tree locks converted to rwsem
patches on btrfs/104:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.9.0+ #102 Not tainted
  ------------------------------------------------------
  btrfs-cleaner/903 is trying to acquire lock:
  ffff8e7fab6ffe30 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x32/0x170

  but task is already holding lock:
  ffff8e7fab628a88 (&fs_info->commit_root_sem){++++}-{3:3}, at: btrfs_find_all_roots+0x41/0x80

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (&fs_info->commit_root_sem){++++}-{3:3}:
	 down_read+0x40/0x130
	 caching_thread+0x53/0x5a0
	 btrfs_work_helper+0xfa/0x520
	 process_one_work+0x238/0x540
	 worker_thread+0x55/0x3c0
	 kthread+0x13a/0x150
	 ret_from_fork+0x1f/0x30

  -> #2 (&caching_ctl->mutex){+.+.}-{3:3}:
	 __mutex_lock+0x7e/0x7b0
	 btrfs_cache_block_group+0x1e0/0x510
	 find_free_extent+0xb6e/0x12f0
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb1/0x330
	 alloc_tree_block_no_bg_flush+0x4f/0x60
	 __btrfs_cow_block+0x11d/0x580
	 btrfs_cow_block+0x10c/0x220
	 commit_cowonly_roots+0x47/0x2e0
	 btrfs_commit_transaction+0x595/0xbd0
	 sync_filesystem+0x74/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x36/0xa0
	 cleanup_mnt+0x12d/0x190
	 task_work_run+0x5c/0xa0
	 exit_to_user_mode_prepare+0x1df/0x200
	 syscall_exit_to_user_mode+0x54/0x280
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&space_info->groups_sem){++++}-{3:3}:
	 down_read+0x40/0x130
	 find_free_extent+0x2ed/0x12f0
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb1/0x330
	 alloc_tree_block_no_bg_flush+0x4f/0x60
	 __btrfs_cow_block+0x11d/0x580
	 btrfs_cow_block+0x10c/0x220
	 commit_cowonly_roots+0x47/0x2e0
	 btrfs_commit_transaction+0x595/0xbd0
	 sync_filesystem+0x74/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x36/0xa0
	 cleanup_mnt+0x12d/0x190
	 task_work_run+0x5c/0xa0
	 exit_to_user_mode_prepare+0x1df/0x200
	 syscall_exit_to_user_mode+0x54/0x280
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (btrfs-root-00){++++}-{3:3}:
	 __lock_acquire+0x1167/0x2150
	 lock_acquire+0xb9/0x3d0
	 down_read_nested+0x43/0x130
	 __btrfs_tree_read_lock+0x32/0x170
	 __btrfs_read_lock_root_node+0x3a/0x50
	 btrfs_search_slot+0x614/0x9d0
	 btrfs_find_root+0x35/0x1b0
	 btrfs_read_tree_root+0x61/0x120
	 btrfs_get_root_ref+0x14b/0x600
	 find_parent_nodes+0x3e6/0x1b30
	 btrfs_find_all_roots_safe+0xb4/0x130
	 btrfs_find_all_roots+0x60/0x80
	 btrfs_qgroup_trace_extent_post+0x27/0x40
	 btrfs_add_delayed_data_ref+0x3fd/0x460
	 btrfs_free_extent+0x42/0x100
	 __btrfs_mod_ref+0x1d7/0x2f0
	 walk_up_proc+0x11c/0x400
	 walk_up_tree+0xf0/0x180
	 btrfs_drop_snapshot+0x1c7/0x780
	 btrfs_clean_one_deleted_snapshot+0xfb/0x110
	 cleaner_kthread+0xd4/0x140
	 kthread+0x13a/0x150
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

  Chain exists of:
    btrfs-root-00 --> &caching_ctl->mutex --> &fs_info->commit_root_sem

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_info->commit_root_sem);
				 lock(&caching_ctl->mutex);
				 lock(&fs_info->commit_root_sem);
    lock(btrfs-root-00);

   *** DEADLOCK ***

  3 locks held by btrfs-cleaner/903:
   #0: ffff8e7fab628838 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: cleaner_kthread+0x6e/0x140
   #1: ffff8e7faadac640 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x40b/0x5c0
   #2: ffff8e7fab628a88 (&fs_info->commit_root_sem){++++}-{3:3}, at: btrfs_find_all_roots+0x41/0x80

  stack backtrace:
  CPU: 0 PID: 903 Comm: btrfs-cleaner Not tainted 5.9.0+ #102
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:
   dump_stack+0x8b/0xb0
   check_noncircular+0xcf/0xf0
   __lock_acquire+0x1167/0x2150
   ? __bfs+0x42/0x210
   lock_acquire+0xb9/0x3d0
   ? __btrfs_tree_read_lock+0x32/0x170
   down_read_nested+0x43/0x130
   ? __btrfs_tree_read_lock+0x32/0x170
   __btrfs_tree_read_lock+0x32/0x170
   __btrfs_read_lock_root_node+0x3a/0x50
   btrfs_search_slot+0x614/0x9d0
   ? find_held_lock+0x2b/0x80
   btrfs_find_root+0x35/0x1b0
   ? do_raw_spin_unlock+0x4b/0xa0
   btrfs_read_tree_root+0x61/0x120
   btrfs_get_root_ref+0x14b/0x600
   find_parent_nodes+0x3e6/0x1b30
   btrfs_find_all_roots_safe+0xb4/0x130
   btrfs_find_all_roots+0x60/0x80
   btrfs_qgroup_trace_extent_post+0x27/0x40
   btrfs_add_delayed_data_ref+0x3fd/0x460
   btrfs_free_extent+0x42/0x100
   __btrfs_mod_ref+0x1d7/0x2f0
   walk_up_proc+0x11c/0x400
   walk_up_tree+0xf0/0x180
   btrfs_drop_snapshot+0x1c7/0x780
   ? btrfs_clean_one_deleted_snapshot+0x73/0x110
   btrfs_clean_one_deleted_snapshot+0xfb/0x110
   cleaner_kthread+0xd4/0x140
   ? btrfs_alloc_root+0x50/0x50
   kthread+0x13a/0x150
   ? kthread_create_worker_on_cpu+0x40/0x40
   ret_from_fork+0x1f/0x30
  BTRFS info (device sdb): disk space caching is enabled
  BTRFS info (device sdb): has skinny extents

This happens because qgroups does a backref lookup when we create a
delayed ref.  From here it may have to look up a root from an indirect
ref, which does a normal lookup on the tree_root, which takes the read
lock on the tree_root nodes.

To fix this we need to add a variant for looking up roots that searches
the commit root of the tree_root.  Then when we do the backref search
using the commit root we are sure to not take any locks on the tree_root
nodes.  This gets rid of the lockdep splat when running btrfs/104.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
popcornmix pushed a commit that referenced this issue Jul 15, 2021
[ Upstream commit 45c8ddd ]

Before referencing 'host->data', the driver needs to check whether it is
null pointer, otherwise it will cause a null pointer reference.

This log reveals it:

[   29.355199] BUG: kernel NULL pointer dereference, address:
0000000000000014
[   29.357323] #PF: supervisor write access in kernel mode
[   29.357706] #PF: error_code(0x0002) - not-present page
[   29.358088] PGD 0 P4D 0
[   29.358280] Oops: 0002 [#1] PREEMPT SMP PTI
[   29.358595] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.12.4-
g70e7f0549188-dirty #102
[   29.359164] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[   29.359978] RIP: 0010:via_sdc_isr+0x21f/0x410
[   29.360314] Code: ff ff e8 84 aa d0 fd 66 45 89 7e 28 66 41 f7 c4 00
10 75 56 e8 72 aa d0 fd 66 41 f7 c4 00 c0 74 10 e8 65 aa d0 fd 48 8b 43
18 <c7> 40 14 ac ff ff ff e8 55 aa d0 fd 48 89 df e8 ad fb ff ff e9 77
[   29.361661] RSP: 0018:ffffc90000118e98 EFLAGS: 00010046
[   29.362042] RAX: 0000000000000000 RBX: ffff888107d77880
RCX: 0000000000000000
[   29.362564] RDX: 0000000000000000 RSI: ffffffff835d20bb
RDI: 00000000ffffffff
[   29.363085] RBP: ffffc90000118ed8 R08: 0000000000000001
R09: 0000000000000001
[   29.363604] R10: 0000000000000000 R11: 0000000000000001
R12: 0000000000008600
[   29.364128] R13: ffff888107d779c8 R14: ffffc90009c00200
R15: 0000000000008000
[   29.364651] FS:  0000000000000000(0000) GS:ffff88817bc80000(0000)
knlGS:0000000000000000
[   29.365235] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   29.365655] CR2: 0000000000000014 CR3: 0000000005a2e000
CR4: 00000000000006e0
[   29.366170] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[   29.366683] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[   29.367197] Call Trace:
[   29.367381]  <IRQ>
[   29.367537]  __handle_irq_event_percpu+0x53/0x3e0
[   29.367916]  handle_irq_event_percpu+0x35/0x90
[   29.368247]  handle_irq_event+0x39/0x60
[   29.368632]  handle_fasteoi_irq+0xc2/0x1d0
[   29.368950]  __common_interrupt+0x7f/0x150
[   29.369254]  common_interrupt+0xb4/0xd0
[   29.369547]  </IRQ>
[   29.369708]  asm_common_interrupt+0x1e/0x40
[   29.370016] RIP: 0010:native_safe_halt+0x17/0x20
[   29.370360] Code: 07 0f 00 2d db 80 43 00 f4 5d c3 0f 1f 84 00 00 00
00 00 8b 05 c2 37 e5 01 55 48 89 e5 85 c0 7e 07 0f 00 2d bb 80 43 00 fb
f4 <5d> c3 cc cc cc cc cc cc cc 55 48 89 e5 e8 67 53 ff ff 8b 0d f9 91
[   29.371696] RSP: 0018:ffffc9000008fe90 EFLAGS: 00000246
[   29.372079] RAX: 0000000000000000 RBX: 0000000000000002
RCX: 0000000000000000
[   29.372595] RDX: 0000000000000000 RSI: ffffffff854f67a4
RDI: ffffffff85403406
[   29.373122] RBP: ffffc9000008fe90 R08: 0000000000000001
R09: 0000000000000001
[   29.373646] R10: 0000000000000000 R11: 0000000000000001
R12: ffffffff86009188
[   29.374160] R13: 0000000000000000 R14: 0000000000000000
R15: ffff888100258000
[   29.374690]  default_idle+0x9/0x10
[   29.374944]  arch_cpu_idle+0xa/0x10
[   29.375198]  default_idle_call+0x6e/0x250
[   29.375491]  do_idle+0x1f0/0x2d0
[   29.375740]  cpu_startup_entry+0x18/0x20
[   29.376034]  start_secondary+0x11f/0x160
[   29.376328]  secondary_startup_64_no_verify+0xb0/0xbb
[   29.376705] Modules linked in:
[   29.376939] Dumping ftrace buffer:
[   29.377187]    (ftrace buffer empty)
[   29.377460] CR2: 0000000000000014
[   29.377712] ---[ end trace 51a473dffb618c47 ]---
[   29.378056] RIP: 0010:via_sdc_isr+0x21f/0x410
[   29.378380] Code: ff ff e8 84 aa d0 fd 66 45 89 7e 28 66 41 f7 c4 00
10 75 56 e8 72 aa d0 fd 66 41 f7 c4 00 c0 74 10 e8 65 aa d0 fd 48 8b 43
18 <c7> 40 14 ac ff ff ff e8 55 aa d0 fd 48 89 df e8 ad fb ff ff e9 77
[   29.379714] RSP: 0018:ffffc90000118e98 EFLAGS: 00010046
[   29.380098] RAX: 0000000000000000 RBX: ffff888107d77880
RCX: 0000000000000000
[   29.380614] RDX: 0000000000000000 RSI: ffffffff835d20bb
RDI: 00000000ffffffff
[   29.381134] RBP: ffffc90000118ed8 R08: 0000000000000001
R09: 0000000000000001
[   29.381653] R10: 0000000000000000 R11: 0000000000000001
R12: 0000000000008600
[   29.382176] R13: ffff888107d779c8 R14: ffffc90009c00200
R15: 0000000000008000
[   29.382697] FS:  0000000000000000(0000) GS:ffff88817bc80000(0000)
knlGS:0000000000000000
[   29.383277] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   29.383697] CR2: 0000000000000014 CR3: 0000000005a2e000
CR4: 00000000000006e0
[   29.384223] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[   29.384736] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[   29.385260] Kernel panic - not syncing: Fatal exception in interrupt
[   29.385882] Dumping ftrace buffer:
[   29.386135]    (ftrace buffer empty)
[   29.386401] Kernel Offset: disabled
[   29.386656] Rebooting in 1 seconds..

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Link: https://lore.kernel.org/r/1622727200-15808-1-git-send-email-zheyuma97@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
popcornmix pushed a commit that referenced this issue Jul 15, 2021
[ Upstream commit 45c8ddd ]

Before referencing 'host->data', the driver needs to check whether it is
null pointer, otherwise it will cause a null pointer reference.

This log reveals it:

[   29.355199] BUG: kernel NULL pointer dereference, address:
0000000000000014
[   29.357323] #PF: supervisor write access in kernel mode
[   29.357706] #PF: error_code(0x0002) - not-present page
[   29.358088] PGD 0 P4D 0
[   29.358280] Oops: 0002 [#1] PREEMPT SMP PTI
[   29.358595] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.12.4-
g70e7f0549188-dirty #102
[   29.359164] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[   29.359978] RIP: 0010:via_sdc_isr+0x21f/0x410
[   29.360314] Code: ff ff e8 84 aa d0 fd 66 45 89 7e 28 66 41 f7 c4 00
10 75 56 e8 72 aa d0 fd 66 41 f7 c4 00 c0 74 10 e8 65 aa d0 fd 48 8b 43
18 <c7> 40 14 ac ff ff ff e8 55 aa d0 fd 48 89 df e8 ad fb ff ff e9 77
[   29.361661] RSP: 0018:ffffc90000118e98 EFLAGS: 00010046
[   29.362042] RAX: 0000000000000000 RBX: ffff888107d77880
RCX: 0000000000000000
[   29.362564] RDX: 0000000000000000 RSI: ffffffff835d20bb
RDI: 00000000ffffffff
[   29.363085] RBP: ffffc90000118ed8 R08: 0000000000000001
R09: 0000000000000001
[   29.363604] R10: 0000000000000000 R11: 0000000000000001
R12: 0000000000008600
[   29.364128] R13: ffff888107d779c8 R14: ffffc90009c00200
R15: 0000000000008000
[   29.364651] FS:  0000000000000000(0000) GS:ffff88817bc80000(0000)
knlGS:0000000000000000
[   29.365235] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   29.365655] CR2: 0000000000000014 CR3: 0000000005a2e000
CR4: 00000000000006e0
[   29.366170] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[   29.366683] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[   29.367197] Call Trace:
[   29.367381]  <IRQ>
[   29.367537]  __handle_irq_event_percpu+0x53/0x3e0
[   29.367916]  handle_irq_event_percpu+0x35/0x90
[   29.368247]  handle_irq_event+0x39/0x60
[   29.368632]  handle_fasteoi_irq+0xc2/0x1d0
[   29.368950]  __common_interrupt+0x7f/0x150
[   29.369254]  common_interrupt+0xb4/0xd0
[   29.369547]  </IRQ>
[   29.369708]  asm_common_interrupt+0x1e/0x40
[   29.370016] RIP: 0010:native_safe_halt+0x17/0x20
[   29.370360] Code: 07 0f 00 2d db 80 43 00 f4 5d c3 0f 1f 84 00 00 00
00 00 8b 05 c2 37 e5 01 55 48 89 e5 85 c0 7e 07 0f 00 2d bb 80 43 00 fb
f4 <5d> c3 cc cc cc cc cc cc cc 55 48 89 e5 e8 67 53 ff ff 8b 0d f9 91
[   29.371696] RSP: 0018:ffffc9000008fe90 EFLAGS: 00000246
[   29.372079] RAX: 0000000000000000 RBX: 0000000000000002
RCX: 0000000000000000
[   29.372595] RDX: 0000000000000000 RSI: ffffffff854f67a4
RDI: ffffffff85403406
[   29.373122] RBP: ffffc9000008fe90 R08: 0000000000000001
R09: 0000000000000001
[   29.373646] R10: 0000000000000000 R11: 0000000000000001
R12: ffffffff86009188
[   29.374160] R13: 0000000000000000 R14: 0000000000000000
R15: ffff888100258000
[   29.374690]  default_idle+0x9/0x10
[   29.374944]  arch_cpu_idle+0xa/0x10
[   29.375198]  default_idle_call+0x6e/0x250
[   29.375491]  do_idle+0x1f0/0x2d0
[   29.375740]  cpu_startup_entry+0x18/0x20
[   29.376034]  start_secondary+0x11f/0x160
[   29.376328]  secondary_startup_64_no_verify+0xb0/0xbb
[   29.376705] Modules linked in:
[   29.376939] Dumping ftrace buffer:
[   29.377187]    (ftrace buffer empty)
[   29.377460] CR2: 0000000000000014
[   29.377712] ---[ end trace 51a473dffb618c47 ]---
[   29.378056] RIP: 0010:via_sdc_isr+0x21f/0x410
[   29.378380] Code: ff ff e8 84 aa d0 fd 66 45 89 7e 28 66 41 f7 c4 00
10 75 56 e8 72 aa d0 fd 66 41 f7 c4 00 c0 74 10 e8 65 aa d0 fd 48 8b 43
18 <c7> 40 14 ac ff ff ff e8 55 aa d0 fd 48 89 df e8 ad fb ff ff e9 77
[   29.379714] RSP: 0018:ffffc90000118e98 EFLAGS: 00010046
[   29.380098] RAX: 0000000000000000 RBX: ffff888107d77880
RCX: 0000000000000000
[   29.380614] RDX: 0000000000000000 RSI: ffffffff835d20bb
RDI: 00000000ffffffff
[   29.381134] RBP: ffffc90000118ed8 R08: 0000000000000001
R09: 0000000000000001
[   29.381653] R10: 0000000000000000 R11: 0000000000000001
R12: 0000000000008600
[   29.382176] R13: ffff888107d779c8 R14: ffffc90009c00200
R15: 0000000000008000
[   29.382697] FS:  0000000000000000(0000) GS:ffff88817bc80000(0000)
knlGS:0000000000000000
[   29.383277] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   29.383697] CR2: 0000000000000014 CR3: 0000000005a2e000
CR4: 00000000000006e0
[   29.384223] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[   29.384736] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[   29.385260] Kernel panic - not syncing: Fatal exception in interrupt
[   29.385882] Dumping ftrace buffer:
[   29.386135]    (ftrace buffer empty)
[   29.386401] Kernel Offset: disabled
[   29.386656] Rebooting in 1 seconds..

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Link: https://lore.kernel.org/r/1622727200-15808-1-git-send-email-zheyuma97@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
popcornmix pushed a commit that referenced this issue Jul 15, 2021
[ Upstream commit 45c8ddd ]

Before referencing 'host->data', the driver needs to check whether it is
null pointer, otherwise it will cause a null pointer reference.

This log reveals it:

[   29.355199] BUG: kernel NULL pointer dereference, address:
0000000000000014
[   29.357323] #PF: supervisor write access in kernel mode
[   29.357706] #PF: error_code(0x0002) - not-present page
[   29.358088] PGD 0 P4D 0
[   29.358280] Oops: 0002 [#1] PREEMPT SMP PTI
[   29.358595] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.12.4-
g70e7f0549188-dirty #102
[   29.359164] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[   29.359978] RIP: 0010:via_sdc_isr+0x21f/0x410
[   29.360314] Code: ff ff e8 84 aa d0 fd 66 45 89 7e 28 66 41 f7 c4 00
10 75 56 e8 72 aa d0 fd 66 41 f7 c4 00 c0 74 10 e8 65 aa d0 fd 48 8b 43
18 <c7> 40 14 ac ff ff ff e8 55 aa d0 fd 48 89 df e8 ad fb ff ff e9 77
[   29.361661] RSP: 0018:ffffc90000118e98 EFLAGS: 00010046
[   29.362042] RAX: 0000000000000000 RBX: ffff888107d77880
RCX: 0000000000000000
[   29.362564] RDX: 0000000000000000 RSI: ffffffff835d20bb
RDI: 00000000ffffffff
[   29.363085] RBP: ffffc90000118ed8 R08: 0000000000000001
R09: 0000000000000001
[   29.363604] R10: 0000000000000000 R11: 0000000000000001
R12: 0000000000008600
[   29.364128] R13: ffff888107d779c8 R14: ffffc90009c00200
R15: 0000000000008000
[   29.364651] FS:  0000000000000000(0000) GS:ffff88817bc80000(0000)
knlGS:0000000000000000
[   29.365235] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   29.365655] CR2: 0000000000000014 CR3: 0000000005a2e000
CR4: 00000000000006e0
[   29.366170] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[   29.366683] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[   29.367197] Call Trace:
[   29.367381]  <IRQ>
[   29.367537]  __handle_irq_event_percpu+0x53/0x3e0
[   29.367916]  handle_irq_event_percpu+0x35/0x90
[   29.368247]  handle_irq_event+0x39/0x60
[   29.368632]  handle_fasteoi_irq+0xc2/0x1d0
[   29.368950]  __common_interrupt+0x7f/0x150
[   29.369254]  common_interrupt+0xb4/0xd0
[   29.369547]  </IRQ>
[   29.369708]  asm_common_interrupt+0x1e/0x40
[   29.370016] RIP: 0010:native_safe_halt+0x17/0x20
[   29.370360] Code: 07 0f 00 2d db 80 43 00 f4 5d c3 0f 1f 84 00 00 00
00 00 8b 05 c2 37 e5 01 55 48 89 e5 85 c0 7e 07 0f 00 2d bb 80 43 00 fb
f4 <5d> c3 cc cc cc cc cc cc cc 55 48 89 e5 e8 67 53 ff ff 8b 0d f9 91
[   29.371696] RSP: 0018:ffffc9000008fe90 EFLAGS: 00000246
[   29.372079] RAX: 0000000000000000 RBX: 0000000000000002
RCX: 0000000000000000
[   29.372595] RDX: 0000000000000000 RSI: ffffffff854f67a4
RDI: ffffffff85403406
[   29.373122] RBP: ffffc9000008fe90 R08: 0000000000000001
R09: 0000000000000001
[   29.373646] R10: 0000000000000000 R11: 0000000000000001
R12: ffffffff86009188
[   29.374160] R13: 0000000000000000 R14: 0000000000000000
R15: ffff888100258000
[   29.374690]  default_idle+0x9/0x10
[   29.374944]  arch_cpu_idle+0xa/0x10
[   29.375198]  default_idle_call+0x6e/0x250
[   29.375491]  do_idle+0x1f0/0x2d0
[   29.375740]  cpu_startup_entry+0x18/0x20
[   29.376034]  start_secondary+0x11f/0x160
[   29.376328]  secondary_startup_64_no_verify+0xb0/0xbb
[   29.376705] Modules linked in:
[   29.376939] Dumping ftrace buffer:
[   29.377187]    (ftrace buffer empty)
[   29.377460] CR2: 0000000000000014
[   29.377712] ---[ end trace 51a473dffb618c47 ]---
[   29.378056] RIP: 0010:via_sdc_isr+0x21f/0x410
[   29.378380] Code: ff ff e8 84 aa d0 fd 66 45 89 7e 28 66 41 f7 c4 00
10 75 56 e8 72 aa d0 fd 66 41 f7 c4 00 c0 74 10 e8 65 aa d0 fd 48 8b 43
18 <c7> 40 14 ac ff ff ff e8 55 aa d0 fd 48 89 df e8 ad fb ff ff e9 77
[   29.379714] RSP: 0018:ffffc90000118e98 EFLAGS: 00010046
[   29.380098] RAX: 0000000000000000 RBX: ffff888107d77880
RCX: 0000000000000000
[   29.380614] RDX: 0000000000000000 RSI: ffffffff835d20bb
RDI: 00000000ffffffff
[   29.381134] RBP: ffffc90000118ed8 R08: 0000000000000001
R09: 0000000000000001
[   29.381653] R10: 0000000000000000 R11: 0000000000000001
R12: 0000000000008600
[   29.382176] R13: ffff888107d779c8 R14: ffffc90009c00200
R15: 0000000000008000
[   29.382697] FS:  0000000000000000(0000) GS:ffff88817bc80000(0000)
knlGS:0000000000000000
[   29.383277] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   29.383697] CR2: 0000000000000014 CR3: 0000000005a2e000
CR4: 00000000000006e0
[   29.384223] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[   29.384736] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[   29.385260] Kernel panic - not syncing: Fatal exception in interrupt
[   29.385882] Dumping ftrace buffer:
[   29.386135]    (ftrace buffer empty)
[   29.386401] Kernel Offset: disabled
[   29.386656] Rebooting in 1 seconds..

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Link: https://lore.kernel.org/r/1622727200-15808-1-git-send-email-zheyuma97@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
angiglesias pushed a commit to angiglesias/raspberry-kernel that referenced this issue Jun 25, 2022
Commit a7259df ("memblock: make memblock_find_in_range method
private") changed the API using which memory is reserved for the pKVM
hypervisor. However, memblock_phys_alloc() differs from the original API in
terms of kmemleak semantics -- the old one didn't report the reserved
regions to kmemleak while the new one does. Unfortunately, when protected
KVM is enabled, all kernel accesses to pKVM-private memory result in a
fatal exception, which can now happen because of kmemleak scans:

$ echo scan > /sys/kernel/debug/kmemleak
[   34.991354] kvm [304]: nVHE hyp BUG at: [<ffff800008fa3750>] __kvm_nvhe_handle_host_mem_abort+0x270/0x290!
[   34.991580] kvm [304]: Hyp Offset: 0xfffe8be807e00000
[   34.991813] Kernel panic - not syncing: HYP panic:
[   34.991813] PS:600003c9 PC:0000f418011a3750 ESR:00000000f2000800
[   34.991813] FAR:ffff000439200000 HPFAR:0000000004792000 PAR:0000000000000000
[   34.991813] VCPU:0000000000000000
[   34.993660] CPU: 0 PID: 304 Comm: bash Not tainted 5.19.0-rc2 raspberrypi#102
[   34.994059] Hardware name: linux,dummy-virt (DT)
[   34.994452] Call trace:
[   34.994641]  dump_backtrace.part.0+0xcc/0xe0
[   34.994932]  show_stack+0x18/0x6c
[   34.995094]  dump_stack_lvl+0x68/0x84
[   34.995276]  dump_stack+0x18/0x34
[   34.995484]  panic+0x16c/0x354
[   34.995673]  __hyp_pgtable_total_pages+0x0/0x60
[   34.995933]  scan_block+0x74/0x12c
[   34.996129]  scan_gray_list+0xd8/0x19c
[   34.996332]  kmemleak_scan+0x2c8/0x580
[   34.996535]  kmemleak_write+0x340/0x4a0
[   34.996744]  full_proxy_write+0x60/0xbc
[   34.996967]  vfs_write+0xc4/0x2b0
[   34.997136]  ksys_write+0x68/0xf4
[   34.997311]  __arm64_sys_write+0x20/0x2c
[   34.997532]  invoke_syscall+0x48/0x114
[   34.997779]  el0_svc_common.constprop.0+0x44/0xec
[   34.998029]  do_el0_svc+0x2c/0xc0
[   34.998205]  el0_svc+0x2c/0x84
[   34.998421]  el0t_64_sync_handler+0xf4/0x100
[   34.998653]  el0t_64_sync+0x18c/0x190
[   34.999252] SMP: stopping secondary CPUs
[   35.000034] Kernel Offset: disabled
[   35.000261] CPU features: 0x800,00007831,00001086
[   35.000642] Memory Limit: none
[   35.001329] ---[ end Kernel panic - not syncing: HYP panic:
[   35.001329] PS:600003c9 PC:0000f418011a3750 ESR:00000000f2000800
[   35.001329] FAR:ffff000439200000 HPFAR:0000000004792000 PAR:0000000000000000
[   35.001329] VCPU:0000000000000000 ]---

Fix this by explicitly excluding the hypervisor's memory pool from
kmemleak like we already do for the hyp BSS.

Cc: Mike Rapoport <rppt@kernel.org>
Fixes: a7259df ("memblock: make memblock_find_in_range method private")
Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220616161135.3997786-1-qperret@google.com
popcornmix pushed a commit that referenced this issue Jul 4, 2022
[ Upstream commit 56961c6 ]

Commit a7259df ("memblock: make memblock_find_in_range method
private") changed the API using which memory is reserved for the pKVM
hypervisor. However, memblock_phys_alloc() differs from the original API in
terms of kmemleak semantics -- the old one didn't report the reserved
regions to kmemleak while the new one does. Unfortunately, when protected
KVM is enabled, all kernel accesses to pKVM-private memory result in a
fatal exception, which can now happen because of kmemleak scans:

$ echo scan > /sys/kernel/debug/kmemleak
[   34.991354] kvm [304]: nVHE hyp BUG at: [<ffff800008fa3750>] __kvm_nvhe_handle_host_mem_abort+0x270/0x290!
[   34.991580] kvm [304]: Hyp Offset: 0xfffe8be807e00000
[   34.991813] Kernel panic - not syncing: HYP panic:
[   34.991813] PS:600003c9 PC:0000f418011a3750 ESR:00000000f2000800
[   34.991813] FAR:ffff000439200000 HPFAR:0000000004792000 PAR:0000000000000000
[   34.991813] VCPU:0000000000000000
[   34.993660] CPU: 0 PID: 304 Comm: bash Not tainted 5.19.0-rc2 #102
[   34.994059] Hardware name: linux,dummy-virt (DT)
[   34.994452] Call trace:
[   34.994641]  dump_backtrace.part.0+0xcc/0xe0
[   34.994932]  show_stack+0x18/0x6c
[   34.995094]  dump_stack_lvl+0x68/0x84
[   34.995276]  dump_stack+0x18/0x34
[   34.995484]  panic+0x16c/0x354
[   34.995673]  __hyp_pgtable_total_pages+0x0/0x60
[   34.995933]  scan_block+0x74/0x12c
[   34.996129]  scan_gray_list+0xd8/0x19c
[   34.996332]  kmemleak_scan+0x2c8/0x580
[   34.996535]  kmemleak_write+0x340/0x4a0
[   34.996744]  full_proxy_write+0x60/0xbc
[   34.996967]  vfs_write+0xc4/0x2b0
[   34.997136]  ksys_write+0x68/0xf4
[   34.997311]  __arm64_sys_write+0x20/0x2c
[   34.997532]  invoke_syscall+0x48/0x114
[   34.997779]  el0_svc_common.constprop.0+0x44/0xec
[   34.998029]  do_el0_svc+0x2c/0xc0
[   34.998205]  el0_svc+0x2c/0x84
[   34.998421]  el0t_64_sync_handler+0xf4/0x100
[   34.998653]  el0t_64_sync+0x18c/0x190
[   34.999252] SMP: stopping secondary CPUs
[   35.000034] Kernel Offset: disabled
[   35.000261] CPU features: 0x800,00007831,00001086
[   35.000642] Memory Limit: none
[   35.001329] ---[ end Kernel panic - not syncing: HYP panic:
[   35.001329] PS:600003c9 PC:0000f418011a3750 ESR:00000000f2000800
[   35.001329] FAR:ffff000439200000 HPFAR:0000000004792000 PAR:0000000000000000
[   35.001329] VCPU:0000000000000000 ]---

Fix this by explicitly excluding the hypervisor's memory pool from
kmemleak like we already do for the hyp BSS.

Cc: Mike Rapoport <rppt@kernel.org>
Fixes: a7259df ("memblock: make memblock_find_in_range method private")
Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220616161135.3997786-1-qperret@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
popcornmix pushed a commit that referenced this issue Jul 4, 2022
[ Upstream commit 56961c6 ]

Commit a7259df ("memblock: make memblock_find_in_range method
private") changed the API using which memory is reserved for the pKVM
hypervisor. However, memblock_phys_alloc() differs from the original API in
terms of kmemleak semantics -- the old one didn't report the reserved
regions to kmemleak while the new one does. Unfortunately, when protected
KVM is enabled, all kernel accesses to pKVM-private memory result in a
fatal exception, which can now happen because of kmemleak scans:

$ echo scan > /sys/kernel/debug/kmemleak
[   34.991354] kvm [304]: nVHE hyp BUG at: [<ffff800008fa3750>] __kvm_nvhe_handle_host_mem_abort+0x270/0x290!
[   34.991580] kvm [304]: Hyp Offset: 0xfffe8be807e00000
[   34.991813] Kernel panic - not syncing: HYP panic:
[   34.991813] PS:600003c9 PC:0000f418011a3750 ESR:00000000f2000800
[   34.991813] FAR:ffff000439200000 HPFAR:0000000004792000 PAR:0000000000000000
[   34.991813] VCPU:0000000000000000
[   34.993660] CPU: 0 PID: 304 Comm: bash Not tainted 5.19.0-rc2 #102
[   34.994059] Hardware name: linux,dummy-virt (DT)
[   34.994452] Call trace:
[   34.994641]  dump_backtrace.part.0+0xcc/0xe0
[   34.994932]  show_stack+0x18/0x6c
[   34.995094]  dump_stack_lvl+0x68/0x84
[   34.995276]  dump_stack+0x18/0x34
[   34.995484]  panic+0x16c/0x354
[   34.995673]  __hyp_pgtable_total_pages+0x0/0x60
[   34.995933]  scan_block+0x74/0x12c
[   34.996129]  scan_gray_list+0xd8/0x19c
[   34.996332]  kmemleak_scan+0x2c8/0x580
[   34.996535]  kmemleak_write+0x340/0x4a0
[   34.996744]  full_proxy_write+0x60/0xbc
[   34.996967]  vfs_write+0xc4/0x2b0
[   34.997136]  ksys_write+0x68/0xf4
[   34.997311]  __arm64_sys_write+0x20/0x2c
[   34.997532]  invoke_syscall+0x48/0x114
[   34.997779]  el0_svc_common.constprop.0+0x44/0xec
[   34.998029]  do_el0_svc+0x2c/0xc0
[   34.998205]  el0_svc+0x2c/0x84
[   34.998421]  el0t_64_sync_handler+0xf4/0x100
[   34.998653]  el0t_64_sync+0x18c/0x190
[   34.999252] SMP: stopping secondary CPUs
[   35.000034] Kernel Offset: disabled
[   35.000261] CPU features: 0x800,00007831,00001086
[   35.000642] Memory Limit: none
[   35.001329] ---[ end Kernel panic - not syncing: HYP panic:
[   35.001329] PS:600003c9 PC:0000f418011a3750 ESR:00000000f2000800
[   35.001329] FAR:ffff000439200000 HPFAR:0000000004792000 PAR:0000000000000000
[   35.001329] VCPU:0000000000000000 ]---

Fix this by explicitly excluding the hypervisor's memory pool from
kmemleak like we already do for the hyp BSS.

Cc: Mike Rapoport <rppt@kernel.org>
Fixes: a7259df ("memblock: make memblock_find_in_range method private")
Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220616161135.3997786-1-qperret@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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