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Use DMI matching for conflicting SSID 0x1f660101 between Ayaneo and AYN #11

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merged 1 commit into from
Jul 27, 2024

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CVMagic
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@CVMagic CVMagic commented Jul 13, 2024

This is after Fewt submitted a patch that appears to apply for all 0x1660103 devices, Previous PR is no longer required for that SSID.

@BoukeHaarsma23
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@CVMagic could you rebase against 6.10/chimeraos for me? They also added the Loki MiniPro there, so I think we need to accomodate there.

@BoukeHaarsma23
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BoukeHaarsma23 commented Jul 27, 2024

Applied on 6.10 via cc972ed

@BoukeHaarsma23 BoukeHaarsma23 merged commit b58e747 into 6.9/chimeraos Jul 27, 2024
@BoukeHaarsma23 BoukeHaarsma23 deleted the CVMagic-patch-2 branch July 28, 2024 12:11
honjow pushed a commit to 3003n/linux that referenced this pull request Aug 4, 2024
[ Upstream commit eef0532 ]

Run bpf_tcp_ca selftests (./test_progs -t bpf_tcp_ca) on a Loongarch
platform, some "Segmentation fault" errors occur:

'''
 test_dctcp:PASS:bpf_dctcp__open_and_load 0 nsec
 test_dctcp:FAIL:bpf_map__attach_struct_ops unexpected error: -524
 torvalds#29/1    bpf_tcp_ca/dctcp:FAIL
 test_cubic:PASS:bpf_cubic__open_and_load 0 nsec
 test_cubic:FAIL:bpf_map__attach_struct_ops unexpected error: -524
 torvalds#29/2    bpf_tcp_ca/cubic:FAIL
 test_dctcp_fallback:PASS:dctcp_skel 0 nsec
 test_dctcp_fallback:PASS:bpf_dctcp__load 0 nsec
 test_dctcp_fallback:FAIL:dctcp link unexpected error: -524
 torvalds#29/4    bpf_tcp_ca/dctcp_fallback:FAIL
 test_write_sk_pacing:PASS:open_and_load 0 nsec
 test_write_sk_pacing:FAIL:attach_struct_ops unexpected error: -524
 torvalds#29/6    bpf_tcp_ca/write_sk_pacing:FAIL
 test_update_ca:PASS:open 0 nsec
 test_update_ca:FAIL:attach_struct_ops unexpected error: -524
 settcpca:FAIL:setsockopt unexpected setsockopt: \
					actual -1 == expected -1
 (network_helpers.c:99: errno: No such file or directory) \
					Failed to call post_socket_cb
 start_test:FAIL:start_server_str unexpected start_server_str: \
					actual -1 == expected -1
 test_update_ca:FAIL:ca1_ca1_cnt unexpected ca1_ca1_cnt: \
					actual 0 <= expected 0
 torvalds#29/9    bpf_tcp_ca/update_ca:FAIL
 torvalds#29      bpf_tcp_ca:FAIL
 Caught signal ChimeraOS#11!
 Stack trace:
 ./test_progs(crash_handler+0x28)[0x5555567ed91c]
 linux-vdso.so.1(__vdso_rt_sigreturn+0x0)[0x7ffffee408b0]
 ./test_progs(bpf_link__update_map+0x80)[0x555556824a78]
 ./test_progs(+0x94d68)[0x5555564c4d68]
 ./test_progs(test_bpf_tcp_ca+0xe8)[0x5555564c6a88]
 ./test_progs(+0x3bde54)[0x5555567ede54]
 ./test_progs(main+0x61c)[0x5555567efd54]
 /usr/lib64/libc.so.6(+0x22208)[0x7ffff2aaa208]
 /usr/lib64/libc.so.6(__libc_start_main+0xac)[0x7ffff2aaa30c]
 ./test_progs(_start+0x48)[0x55555646bca8]
 Segmentation fault
'''

This is because BPF trampoline is not implemented on Loongarch yet,
"link" returned by bpf_map__attach_struct_ops() is NULL. test_progs
crashs when this NULL link passes to bpf_link__update_map(). This
patch adds NULL checks for all links in bpf_tcp_ca to fix these errors.
If "link" is NULL, goto the newly added label "out" to destroy the skel.

v2:
 - use "goto out" instead of "return" as Eduard suggested.

Fixes: 06da9f3 ("selftests/bpf: Test switching TCP Congestion Control algorithms.")
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/r/b4c841492bd4ed97964e4e61e92827ce51bf1dc9.1720615848.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
BoukeHaarsma23 pushed a commit that referenced this pull request Aug 29, 2024
[ Upstream commit 8baeef7 ]

Remove the dma_unmap_page_attrs() call in the driver's XDP_REDIRECT
code path.  This should have been removed when we let the page pool
handle the DMA mapping.  This bug causes the warning:

WARNING: CPU: 7 PID: 59 at drivers/iommu/dma-iommu.c:1198 iommu_dma_unmap_page+0xd5/0x100
CPU: 7 PID: 59 Comm: ksoftirqd/7 Tainted: G        W          6.8.0-1010-gcp #11-Ubuntu
Hardware name: Dell Inc. PowerEdge R7525/0PYVT1, BIOS 2.15.2 04/02/2024
RIP: 0010:iommu_dma_unmap_page+0xd5/0x100
Code: 89 ee 48 89 df e8 cb f2 69 ff 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 31 d2 31 c9 31 f6 31 ff 45 31 c0 e9 ab 17 71 00 <0f> 0b 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 31 d2 31 c9
RSP: 0018:ffffab1fc0597a48 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff99ff838280c8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffab1fc0597a78 R08: 0000000000000002 R09: ffffab1fc0597c1c
R10: ffffab1fc0597cd3 R11: ffff99ffe375acd8 R12: 00000000e65b9000
R13: 0000000000000050 R14: 0000000000001000 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff9a06efb80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000565c34c37210 CR3: 00000005c7e3e000 CR4: 0000000000350ef0
? show_regs+0x6d/0x80
? __warn+0x89/0x150
? iommu_dma_unmap_page+0xd5/0x100
? report_bug+0x16a/0x190
? handle_bug+0x51/0xa0
? exc_invalid_op+0x18/0x80
? iommu_dma_unmap_page+0xd5/0x100
? iommu_dma_unmap_page+0x35/0x100
dma_unmap_page_attrs+0x55/0x220
? bpf_prog_4d7e87c0d30db711_xdp_dispatcher+0x64/0x9f
bnxt_rx_xdp+0x237/0x520 [bnxt_en]
bnxt_rx_pkt+0x640/0xdd0 [bnxt_en]
__bnxt_poll_work+0x1a1/0x3d0 [bnxt_en]
bnxt_poll+0xaa/0x1e0 [bnxt_en]
__napi_poll+0x33/0x1e0
net_rx_action+0x18a/0x2f0

Fixes: 578fcfd ("bnxt_en: Let the page pool manage the DMA mapping")
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20240820203415.168178-1-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
flukejones pushed a commit to flukejones/linux that referenced this pull request Aug 31, 2024
Remove the dma_unmap_page_attrs() call in the driver's XDP_REDIRECT
code path.  This should have been removed when we let the page pool
handle the DMA mapping.  This bug causes the warning:

WARNING: CPU: 7 PID: 59 at drivers/iommu/dma-iommu.c:1198 iommu_dma_unmap_page+0xd5/0x100
CPU: 7 PID: 59 Comm: ksoftirqd/7 Tainted: G        W          6.8.0-1010-gcp ChimeraOS#11-Ubuntu
Hardware name: Dell Inc. PowerEdge R7525/0PYVT1, BIOS 2.15.2 04/02/2024
RIP: 0010:iommu_dma_unmap_page+0xd5/0x100
Code: 89 ee 48 89 df e8 cb f2 69 ff 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 31 d2 31 c9 31 f6 31 ff 45 31 c0 e9 ab 17 71 00 <0f> 0b 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 31 d2 31 c9
RSP: 0018:ffffab1fc0597a48 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff99ff838280c8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffab1fc0597a78 R08: 0000000000000002 R09: ffffab1fc0597c1c
R10: ffffab1fc0597cd3 R11: ffff99ffe375acd8 R12: 00000000e65b9000
R13: 0000000000000050 R14: 0000000000001000 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff9a06efb80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000565c34c37210 CR3: 00000005c7e3e000 CR4: 0000000000350ef0
? show_regs+0x6d/0x80
? __warn+0x89/0x150
? iommu_dma_unmap_page+0xd5/0x100
? report_bug+0x16a/0x190
? handle_bug+0x51/0xa0
? exc_invalid_op+0x18/0x80
? iommu_dma_unmap_page+0xd5/0x100
? iommu_dma_unmap_page+0x35/0x100
dma_unmap_page_attrs+0x55/0x220
? bpf_prog_4d7e87c0d30db711_xdp_dispatcher+0x64/0x9f
bnxt_rx_xdp+0x237/0x520 [bnxt_en]
bnxt_rx_pkt+0x640/0xdd0 [bnxt_en]
__bnxt_poll_work+0x1a1/0x3d0 [bnxt_en]
bnxt_poll+0xaa/0x1e0 [bnxt_en]
__napi_poll+0x33/0x1e0
net_rx_action+0x18a/0x2f0

Fixes: 578fcfd ("bnxt_en: Let the page pool manage the DMA mapping")
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20240820203415.168178-1-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
flukejones pushed a commit to flukejones/linux that referenced this pull request Aug 31, 2024
A sysfs reader can race with a device reset or removal, attempting to
read device state when the device is not actually present. eg:

     [exception RIP: qed_get_current_link+17]
  ChimeraOS#8 [ffffb9e4f2907c48] qede_get_link_ksettings at ffffffffc07a994a [qede]
  ChimeraOS#9 [ffffb9e4f2907cd8] __rh_call_get_link_ksettings at ffffffff992b01a3
 ChimeraOS#10 [ffffb9e4f2907d38] __ethtool_get_link_ksettings at ffffffff992b04e4
 ChimeraOS#11 [ffffb9e4f2907d90] duplex_show at ffffffff99260300
 ChimeraOS#12 [ffffb9e4f2907e38] dev_attr_show at ffffffff9905a01c
 ChimeraOS#13 [ffffb9e4f2907e50] sysfs_kf_seq_show at ffffffff98e0145b
 ChimeraOS#14 [ffffb9e4f2907e68] seq_read at ffffffff98d902e3
 ChimeraOS#15 [ffffb9e4f2907ec8] vfs_read at ffffffff98d657d1
 ChimeraOS#16 [ffffb9e4f2907f00] ksys_read at ffffffff98d65c3f
 ChimeraOS#17 [ffffb9e4f2907f38] do_syscall_64 at ffffffff98a052fb

 crash> struct net_device.state ffff9a9d21336000
    state = 5,

state 5 is __LINK_STATE_START (0b1) and __LINK_STATE_NOCARRIER (0b100).
The device is not present, note lack of __LINK_STATE_PRESENT (0b10).

This is the same sort of panic as observed in commit 4224cfd
("net-sysfs: add check for netdevice being present to speed_show").

There are many other callers of __ethtool_get_link_ksettings() which
don't have a device presence check.

Move this check into ethtool to protect all callers.

Fixes: d519e17 ("net: export device speed and duplex via sysfs")
Fixes: 4224cfd ("net-sysfs: add check for netdevice being present to speed_show")
Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com>
Link: https://patch.msgid.link/8bae218864beaa44ed01628140475b9bf641c5b0.1724393671.git.jamie.bainbridge@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
flukejones pushed a commit to flukejones/linux that referenced this pull request Sep 3, 2024
A sysfs reader can race with a device reset or removal, attempting to
read device state when the device is not actually present. eg:

     [exception RIP: qed_get_current_link+17]
  ChimeraOS#8 [ffffb9e4f2907c48] qede_get_link_ksettings at ffffffffc07a994a [qede]
  ChimeraOS#9 [ffffb9e4f2907cd8] __rh_call_get_link_ksettings at ffffffff992b01a3
 ChimeraOS#10 [ffffb9e4f2907d38] __ethtool_get_link_ksettings at ffffffff992b04e4
 ChimeraOS#11 [ffffb9e4f2907d90] duplex_show at ffffffff99260300
 ChimeraOS#12 [ffffb9e4f2907e38] dev_attr_show at ffffffff9905a01c
 ChimeraOS#13 [ffffb9e4f2907e50] sysfs_kf_seq_show at ffffffff98e0145b
 ChimeraOS#14 [ffffb9e4f2907e68] seq_read at ffffffff98d902e3
 ChimeraOS#15 [ffffb9e4f2907ec8] vfs_read at ffffffff98d657d1
 ChimeraOS#16 [ffffb9e4f2907f00] ksys_read at ffffffff98d65c3f
 ChimeraOS#17 [ffffb9e4f2907f38] do_syscall_64 at ffffffff98a052fb

 crash> struct net_device.state ffff9a9d21336000
    state = 5,

state 5 is __LINK_STATE_START (0b1) and __LINK_STATE_NOCARRIER (0b100).
The device is not present, note lack of __LINK_STATE_PRESENT (0b10).

This is the same sort of panic as observed in commit 4224cfd
("net-sysfs: add check for netdevice being present to speed_show").

There are many other callers of __ethtool_get_link_ksettings() which
don't have a device presence check.

Move this check into ethtool to protect all callers.

Fixes: d519e17 ("net: export device speed and duplex via sysfs")
Fixes: 4224cfd ("net-sysfs: add check for netdevice being present to speed_show")
Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com>
Link: https://patch.msgid.link/8bae218864beaa44ed01628140475b9bf641c5b0.1724393671.git.jamie.bainbridge@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
flukejones pushed a commit to flukejones/linux that referenced this pull request Sep 6, 2024
[ Upstream commit a699781 ]

A sysfs reader can race with a device reset or removal, attempting to
read device state when the device is not actually present. eg:

     [exception RIP: qed_get_current_link+17]
  ChimeraOS#8 [ffffb9e4f2907c48] qede_get_link_ksettings at ffffffffc07a994a [qede]
  ChimeraOS#9 [ffffb9e4f2907cd8] __rh_call_get_link_ksettings at ffffffff992b01a3
 ChimeraOS#10 [ffffb9e4f2907d38] __ethtool_get_link_ksettings at ffffffff992b04e4
 ChimeraOS#11 [ffffb9e4f2907d90] duplex_show at ffffffff99260300
 ChimeraOS#12 [ffffb9e4f2907e38] dev_attr_show at ffffffff9905a01c
 ChimeraOS#13 [ffffb9e4f2907e50] sysfs_kf_seq_show at ffffffff98e0145b
 ChimeraOS#14 [ffffb9e4f2907e68] seq_read at ffffffff98d902e3
 ChimeraOS#15 [ffffb9e4f2907ec8] vfs_read at ffffffff98d657d1
 ChimeraOS#16 [ffffb9e4f2907f00] ksys_read at ffffffff98d65c3f
 ChimeraOS#17 [ffffb9e4f2907f38] do_syscall_64 at ffffffff98a052fb

 crash> struct net_device.state ffff9a9d21336000
    state = 5,

state 5 is __LINK_STATE_START (0b1) and __LINK_STATE_NOCARRIER (0b100).
The device is not present, note lack of __LINK_STATE_PRESENT (0b10).

This is the same sort of panic as observed in commit 4224cfd
("net-sysfs: add check for netdevice being present to speed_show").

There are many other callers of __ethtool_get_link_ksettings() which
don't have a device presence check.

Move this check into ethtool to protect all callers.

Fixes: d519e17 ("net: export device speed and duplex via sysfs")
Fixes: 4224cfd ("net-sysfs: add check for netdevice being present to speed_show")
Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com>
Link: https://patch.msgid.link/8bae218864beaa44ed01628140475b9bf641c5b0.1724393671.git.jamie.bainbridge@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
honjow pushed a commit to 3003n/linux that referenced this pull request Oct 11, 2024
commit 23dfdb5 upstream.

The following kernel trace can be triggered with fstest generic/629 when
executed against a filesystem with fast-commit feature enabled:

INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 0 PID: 866 Comm: mount Not tainted 6.10.0+ ChimeraOS#11
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-prebuilt.qemu.org 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x66/0x90
 register_lock_class+0x759/0x7d0
 __lock_acquire+0x85/0x2630
 ? __find_get_block+0xb4/0x380
 lock_acquire+0xd1/0x2d0
 ? __ext4_journal_get_write_access+0xd5/0x160
 _raw_spin_lock+0x33/0x40
 ? __ext4_journal_get_write_access+0xd5/0x160
 __ext4_journal_get_write_access+0xd5/0x160
 ext4_reserve_inode_write+0x61/0xb0
 __ext4_mark_inode_dirty+0x79/0x270
 ? ext4_ext_replay_set_iblocks+0x2f8/0x450
 ext4_ext_replay_set_iblocks+0x330/0x450
 ext4_fc_replay+0x14c8/0x1540
 ? jread+0x88/0x2e0
 ? rcu_is_watching+0x11/0x40
 do_one_pass+0x447/0xd00
 jbd2_journal_recover+0x139/0x1b0
 jbd2_journal_load+0x96/0x390
 ext4_load_and_init_journal+0x253/0xd40
 ext4_fill_super+0x2cc6/0x3180
...

In the replay path there's an attempt to lock sbi->s_bdev_wb_lock in
function ext4_check_bdev_write_error().  Unfortunately, at this point this
spinlock has not been initialized yet.  Moving it's initialization to an
earlier point in __ext4_fill_super() fixes this splat.

Signed-off-by: Luis Henriques (SUSE) <luis.henriques@linux.dev>
Link: https://patch.msgid.link/20240718094356.7863-1-luis.henriques@linux.dev
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
honjow pushed a commit to 3003n/linux that referenced this pull request Oct 11, 2024
commit ac01c8c upstream.

AddressSanitizer found a use-after-free bug in the symbol code which
manifested as 'perf top' segfaulting.

  ==1238389==ERROR: AddressSanitizer: heap-use-after-free on address 0x60b00c48844b at pc 0x5650d8035961 bp 0x7f751aaecc90 sp 0x7f751aaecc80
  READ of size 1 at 0x60b00c48844b thread T193
      #0 0x5650d8035960 in _sort__sym_cmp util/sort.c:310
      #1 0x5650d8043744 in hist_entry__cmp util/hist.c:1286
      #2 0x5650d8043951 in hists__findnew_entry util/hist.c:614
      ChimeraOS#3 0x5650d804568f in __hists__add_entry util/hist.c:754
      ChimeraOS#4 0x5650d8045bf9 in hists__add_entry util/hist.c:772
      ChimeraOS#5 0x5650d8045df1 in iter_add_single_normal_entry util/hist.c:997
      ChimeraOS#6 0x5650d8043326 in hist_entry_iter__add util/hist.c:1242
      ChimeraOS#7 0x5650d7ceeefe in perf_event__process_sample /home/matt/src/linux/tools/perf/builtin-top.c:845
      ChimeraOS#8 0x5650d7ceeefe in deliver_event /home/matt/src/linux/tools/perf/builtin-top.c:1208
      ChimeraOS#9 0x5650d7fdb51b in do_flush util/ordered-events.c:245
      ChimeraOS#10 0x5650d7fdb51b in __ordered_events__flush util/ordered-events.c:324
      ChimeraOS#11 0x5650d7ced743 in process_thread /home/matt/src/linux/tools/perf/builtin-top.c:1120
      ChimeraOS#12 0x7f757ef1f133 in start_thread nptl/pthread_create.c:442
      ChimeraOS#13 0x7f757ef9f7db in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

When updating hist maps it's also necessary to update the hist symbol
reference because the old one gets freed in map__put().

While this bug was probably introduced with 5c24b67 ("perf
tools: Replace map->referenced & maps->removed_maps with map->refcnt"),
the symbol objects were leaked until c087e94 ("perf machine:
Fix refcount usage when processing PERF_RECORD_KSYMBOL") was merged so
the bug was masked.

Fixes: c087e94 ("perf machine: Fix refcount usage when processing PERF_RECORD_KSYMBOL")
Reported-by: Yunzhao Li <yunzhao@cloudflare.com>
Signed-off-by: Matt Fleming (Cloudflare) <matt@readmodwrite.com>
Cc: Ian Rogers <irogers@google.com>
Cc: kernel-team@cloudflare.com
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: stable@vger.kernel.org # v5.13+
Link: https://lore.kernel.org/r/20240815142212.3834625-1-matt@readmodwrite.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
honjow pushed a commit to 3003n/linux that referenced this pull request Oct 11, 2024
commit 9af2efe upstream.

The fields in the hist_entry are filled on-demand which means they only
have meaningful values when relevant sort keys are used.

So if neither of 'dso' nor 'sym' sort keys are used, the map/symbols in
the hist entry can be garbage.  So it shouldn't access it
unconditionally.

I got a segfault, when I wanted to see cgroup profiles.

  $ sudo perf record -a --all-cgroups --synth=cgroup true

  $ sudo perf report -s cgroup

  Program received signal SIGSEGV, Segmentation fault.
  0x00005555557a8d90 in map__dso (map=0x0) at util/map.h:48
  48		return RC_CHK_ACCESS(map)->dso;
  (gdb) bt
  #0  0x00005555557a8d90 in map__dso (map=0x0) at util/map.h:48
  #1  0x00005555557aa39b in map__load (map=0x0) at util/map.c:344
  #2  0x00005555557aa592 in map__find_symbol (map=0x0, addr=140736115941088) at util/map.c:385
  ChimeraOS#3  0x00005555557ef000 in hists__findnew_entry (hists=0x555556039d60, entry=0x7fffffffa4c0, al=0x7fffffffa8c0, sample_self=true)
      at util/hist.c:644
  ChimeraOS#4  0x00005555557ef61c in __hists__add_entry (hists=0x555556039d60, al=0x7fffffffa8c0, sym_parent=0x0, bi=0x0, mi=0x0, ki=0x0,
      block_info=0x0, sample=0x7fffffffaa90, sample_self=true, ops=0x0) at util/hist.c:761
  ChimeraOS#5  0x00005555557ef71f in hists__add_entry (hists=0x555556039d60, al=0x7fffffffa8c0, sym_parent=0x0, bi=0x0, mi=0x0, ki=0x0,
      sample=0x7fffffffaa90, sample_self=true) at util/hist.c:779
  ChimeraOS#6  0x00005555557f00fb in iter_add_single_normal_entry (iter=0x7fffffffa900, al=0x7fffffffa8c0) at util/hist.c:1015
  ChimeraOS#7  0x00005555557f09a7 in hist_entry_iter__add (iter=0x7fffffffa900, al=0x7fffffffa8c0, max_stack_depth=127, arg=0x7fffffffbce0)
      at util/hist.c:1260
  ChimeraOS#8  0x00005555555ba7ce in process_sample_event (tool=0x7fffffffbce0, event=0x7ffff7c14128, sample=0x7fffffffaa90, evsel=0x555556039ad0,
      machine=0x5555560388e8) at builtin-report.c:334
  ChimeraOS#9  0x00005555557b30c8 in evlist__deliver_sample (evlist=0x555556039010, tool=0x7fffffffbce0, event=0x7ffff7c14128,
      sample=0x7fffffffaa90, evsel=0x555556039ad0, machine=0x5555560388e8) at util/session.c:1232
  ChimeraOS#10 0x00005555557b32bc in machines__deliver_event (machines=0x5555560388e8, evlist=0x555556039010, event=0x7ffff7c14128,
      sample=0x7fffffffaa90, tool=0x7fffffffbce0, file_offset=110888, file_path=0x555556038ff0 "perf.data") at util/session.c:1271
  ChimeraOS#11 0x00005555557b3848 in perf_session__deliver_event (session=0x5555560386d0, event=0x7ffff7c14128, tool=0x7fffffffbce0,
      file_offset=110888, file_path=0x555556038ff0 "perf.data") at util/session.c:1354
  ChimeraOS#12 0x00005555557affaf in ordered_events__deliver_event (oe=0x555556038e60, event=0x555556135aa0) at util/session.c:132
  ChimeraOS#13 0x00005555557bb605 in do_flush (oe=0x555556038e60, show_progress=false) at util/ordered-events.c:245
  ChimeraOS#14 0x00005555557bb95c in __ordered_events__flush (oe=0x555556038e60, how=OE_FLUSH__ROUND, timestamp=0) at util/ordered-events.c:324
  ChimeraOS#15 0x00005555557bba46 in ordered_events__flush (oe=0x555556038e60, how=OE_FLUSH__ROUND) at util/ordered-events.c:342
  ChimeraOS#16 0x00005555557b1b3b in perf_event__process_finished_round (tool=0x7fffffffbce0, event=0x7ffff7c15bb8, oe=0x555556038e60)
      at util/session.c:780
  ChimeraOS#17 0x00005555557b3b27 in perf_session__process_user_event (session=0x5555560386d0, event=0x7ffff7c15bb8, file_offset=117688,
      file_path=0x555556038ff0 "perf.data") at util/session.c:1406

As you can see the entry->ms.map was NULL even if he->ms.map has a
value.  This is because 'sym' sort key is not given, so it cannot assume
whether he->ms.sym and entry->ms.sym is the same.  I only checked the
'sym' sort key here as it implies 'dso' behavior (so maps are the same).

Fixes: ac01c8c ("perf hist: Update hist symbol when updating maps")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Matt Fleming <matt@readmodwrite.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240826221045.1202305-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
honjow pushed a commit to 3003n/linux that referenced this pull request Oct 23, 2024
commit e972b08 upstream.

We're seeing crashes from rq_qos_wake_function that look like this:

  BUG: unable to handle page fault for address: ffffafe180a40084
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 100000067 P4D 100000067 PUD 10027c067 PMD 10115d067 PTE 0
  Oops: Oops: 0002 [#1] PREEMPT SMP PTI
  CPU: 17 UID: 0 PID: 0 Comm: swapper/17 Not tainted 6.12.0-rc3-00013-geca631b8fe80 ChimeraOS#11
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
  RIP: 0010:_raw_spin_lock_irqsave+0x1d/0x40
  Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 41 54 9c 41 5c fa 65 ff 05 62 97 30 4c 31 c0 ba 01 00 00 00 <f0> 0f b1 17 75 0a 4c 89 e0 41 5c c3 cc cc cc cc 89 c6 e8 2c 0b 00
  RSP: 0018:ffffafe180580ca0 EFLAGS: 00010046
  RAX: 0000000000000000 RBX: ffffafe180a3f7a8 RCX: 0000000000000011
  RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffffafe180a40084
  RBP: 0000000000000000 R08: 00000000001e7240 R09: 0000000000000011
  R10: 0000000000000028 R11: 0000000000000888 R12: 0000000000000002
  R13: ffffafe180a40084 R14: 0000000000000000 R15: 0000000000000003
  FS:  0000000000000000(0000) GS:ffff9aaf1f280000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffafe180a40084 CR3: 000000010e428002 CR4: 0000000000770ef0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  PKRU: 55555554
  Call Trace:
   <IRQ>
   try_to_wake_up+0x5a/0x6a0
   rq_qos_wake_function+0x71/0x80
   __wake_up_common+0x75/0xa0
   __wake_up+0x36/0x60
   scale_up.part.0+0x50/0x110
   wb_timer_fn+0x227/0x450
   ...

So rq_qos_wake_function() calls wake_up_process(data->task), which calls
try_to_wake_up(), which faults in raw_spin_lock_irqsave(&p->pi_lock).

p comes from data->task, and data comes from the waitqueue entry, which
is stored on the waiter's stack in rq_qos_wait(). Analyzing the core
dump with drgn, I found that the waiter had already woken up and moved
on to a completely unrelated code path, clobbering what was previously
data->task. Meanwhile, the waker was passing the clobbered garbage in
data->task to wake_up_process(), leading to the crash.

What's happening is that in between rq_qos_wake_function() deleting the
waitqueue entry and calling wake_up_process(), rq_qos_wait() is finding
that it already got a token and returning. The race looks like this:

rq_qos_wait()                           rq_qos_wake_function()
==============================================================
prepare_to_wait_exclusive()
                                        data->got_token = true;
                                        list_del_init(&curr->entry);
if (data.got_token)
        break;
finish_wait(&rqw->wait, &data.wq);
  ^- returns immediately because
     list_empty_careful(&wq_entry->entry)
     is true
... return, go do something else ...
                                        wake_up_process(data->task)
                                          (NO LONGER VALID!)-^

Normally, finish_wait() is supposed to synchronize against the waker.
But, as noted above, it is returning immediately because the waitqueue
entry has already been removed from the waitqueue.

The bug is that rq_qos_wake_function() is accessing the waitqueue entry
AFTER deleting it. Note that autoremove_wake_function() wakes the waiter
and THEN deletes the waitqueue entry, which is the proper order.

Fix it by swapping the order. We also need to use
list_del_init_careful() to match the list_empty_careful() in
finish_wait().

Fixes: 38cfb5a ("blk-wbt: improve waking of tasks")
Cc: stable@vger.kernel.org
Signed-off-by: Omar Sandoval <osandov@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/d3bee2463a67b1ee597211823bf7ad3721c26e41.1729014591.git.osandov@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
flukejones pushed a commit to flukejones/linux that referenced this pull request Oct 23, 2024
We're seeing crashes from rq_qos_wake_function that look like this:

  BUG: unable to handle page fault for address: ffffafe180a40084
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 100000067 P4D 100000067 PUD 10027c067 PMD 10115d067 PTE 0
  Oops: Oops: 0002 [ChimeraOS#1] PREEMPT SMP PTI
  CPU: 17 UID: 0 PID: 0 Comm: swapper/17 Not tainted 6.12.0-rc3-00013-geca631b8fe80 ChimeraOS#11
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
  RIP: 0010:_raw_spin_lock_irqsave+0x1d/0x40
  Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 41 54 9c 41 5c fa 65 ff 05 62 97 30 4c 31 c0 ba 01 00 00 00 <f0> 0f b1 17 75 0a 4c 89 e0 41 5c c3 cc cc cc cc 89 c6 e8 2c 0b 00
  RSP: 0018:ffffafe180580ca0 EFLAGS: 00010046
  RAX: 0000000000000000 RBX: ffffafe180a3f7a8 RCX: 0000000000000011
  RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffffafe180a40084
  RBP: 0000000000000000 R08: 00000000001e7240 R09: 0000000000000011
  R10: 0000000000000028 R11: 0000000000000888 R12: 0000000000000002
  R13: ffffafe180a40084 R14: 0000000000000000 R15: 0000000000000003
  FS:  0000000000000000(0000) GS:ffff9aaf1f280000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffafe180a40084 CR3: 000000010e428002 CR4: 0000000000770ef0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  PKRU: 55555554
  Call Trace:
   <IRQ>
   try_to_wake_up+0x5a/0x6a0
   rq_qos_wake_function+0x71/0x80
   __wake_up_common+0x75/0xa0
   __wake_up+0x36/0x60
   scale_up.part.0+0x50/0x110
   wb_timer_fn+0x227/0x450
   ...

So rq_qos_wake_function() calls wake_up_process(data->task), which calls
try_to_wake_up(), which faults in raw_spin_lock_irqsave(&p->pi_lock).

p comes from data->task, and data comes from the waitqueue entry, which
is stored on the waiter's stack in rq_qos_wait(). Analyzing the core
dump with drgn, I found that the waiter had already woken up and moved
on to a completely unrelated code path, clobbering what was previously
data->task. Meanwhile, the waker was passing the clobbered garbage in
data->task to wake_up_process(), leading to the crash.

What's happening is that in between rq_qos_wake_function() deleting the
waitqueue entry and calling wake_up_process(), rq_qos_wait() is finding
that it already got a token and returning. The race looks like this:

rq_qos_wait()                           rq_qos_wake_function()
==============================================================
prepare_to_wait_exclusive()
                                        data->got_token = true;
                                        list_del_init(&curr->entry);
if (data.got_token)
        break;
finish_wait(&rqw->wait, &data.wq);
  ^- returns immediately because
     list_empty_careful(&wq_entry->entry)
     is true
... return, go do something else ...
                                        wake_up_process(data->task)
                                          (NO LONGER VALID!)-^

Normally, finish_wait() is supposed to synchronize against the waker.
But, as noted above, it is returning immediately because the waitqueue
entry has already been removed from the waitqueue.

The bug is that rq_qos_wake_function() is accessing the waitqueue entry
AFTER deleting it. Note that autoremove_wake_function() wakes the waiter
and THEN deletes the waitqueue entry, which is the proper order.

Fix it by swapping the order. We also need to use
list_del_init_careful() to match the list_empty_careful() in
finish_wait().

Fixes: 38cfb5a ("blk-wbt: improve waking of tasks")
Cc: stable@vger.kernel.org
Signed-off-by: Omar Sandoval <osandov@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/d3bee2463a67b1ee597211823bf7ad3721c26e41.1729014591.git.osandov@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
NeroReflex pushed a commit to NeroReflex/linux that referenced this pull request Nov 6, 2024
Enabling CONFIG_PROVE_RCU_LIST with its dependence CONFIG_RCU_EXPERT
creates this splat when an MPTCP socket is created:

  =============================
  WARNING: suspicious RCU usage
  6.12.0-rc2+ ChimeraOS#11 Not tainted
  -----------------------------
  net/mptcp/sched.c:44 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by mptcp_connect/176.

  stack backtrace:
  CPU: 0 UID: 0 PID: 176 Comm: mptcp_connect Not tainted 6.12.0-rc2+ ChimeraOS#11
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  Call Trace:
   <TASK>
   dump_stack_lvl (lib/dump_stack.c:123)
   lockdep_rcu_suspicious (kernel/locking/lockdep.c:6822)
   mptcp_sched_find (net/mptcp/sched.c:44 (discriminator 7))
   mptcp_init_sock (net/mptcp/protocol.c:2867 (discriminator 1))
   ? sock_init_data_uid (arch/x86/include/asm/atomic.h:28)
   inet_create.part.0.constprop.0 (net/ipv4/af_inet.c:386)
   ? __sock_create (include/linux/rcupdate.h:347 (discriminator 1))
   __sock_create (net/socket.c:1576)
   __sys_socket (net/socket.c:1671)
   ? __pfx___sys_socket (net/socket.c:1712)
   ? do_user_addr_fault (arch/x86/mm/fault.c:1419 (discriminator 1))
   __x64_sys_socket (net/socket.c:1728)
   do_syscall_64 (arch/x86/entry/common.c:52 (discriminator 1))
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

That's because when the socket is initialised, rcu_read_lock() is not
used despite the explicit comment written above the declaration of
mptcp_sched_find() in sched.c. Adding the missing lock/unlock avoids the
warning.

Fixes: 1730b2b ("mptcp: add sched in mptcp_sock")
Cc: stable@vger.kernel.org
Closes: multipath-tcp/mptcp_net-next#523
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241021-net-mptcp-sched-lock-v1-1-637759cf061c@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
honjow pushed a commit to 3003n/linux that referenced this pull request Nov 9, 2024
[ Upstream commit 3deb12c ]

Enabling CONFIG_PROVE_RCU_LIST with its dependence CONFIG_RCU_EXPERT
creates this splat when an MPTCP socket is created:

  =============================
  WARNING: suspicious RCU usage
  6.12.0-rc2+ ChimeraOS#11 Not tainted
  -----------------------------
  net/mptcp/sched.c:44 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by mptcp_connect/176.

  stack backtrace:
  CPU: 0 UID: 0 PID: 176 Comm: mptcp_connect Not tainted 6.12.0-rc2+ ChimeraOS#11
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  Call Trace:
   <TASK>
   dump_stack_lvl (lib/dump_stack.c:123)
   lockdep_rcu_suspicious (kernel/locking/lockdep.c:6822)
   mptcp_sched_find (net/mptcp/sched.c:44 (discriminator 7))
   mptcp_init_sock (net/mptcp/protocol.c:2867 (discriminator 1))
   ? sock_init_data_uid (arch/x86/include/asm/atomic.h:28)
   inet_create.part.0.constprop.0 (net/ipv4/af_inet.c:386)
   ? __sock_create (include/linux/rcupdate.h:347 (discriminator 1))
   __sock_create (net/socket.c:1576)
   __sys_socket (net/socket.c:1671)
   ? __pfx___sys_socket (net/socket.c:1712)
   ? do_user_addr_fault (arch/x86/mm/fault.c:1419 (discriminator 1))
   __x64_sys_socket (net/socket.c:1728)
   do_syscall_64 (arch/x86/entry/common.c:52 (discriminator 1))
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

That's because when the socket is initialised, rcu_read_lock() is not
used despite the explicit comment written above the declaration of
mptcp_sched_find() in sched.c. Adding the missing lock/unlock avoids the
warning.

Fixes: 1730b2b ("mptcp: add sched in mptcp_sock")
Cc: stable@vger.kernel.org
Closes: multipath-tcp/mptcp_net-next#523
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241021-net-mptcp-sched-lock-v1-1-637759cf061c@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
flukejones pushed a commit to flukejones/linux that referenced this pull request Nov 18, 2024
Disable strict aliasing, as has been done in the kernel proper for decades
(literally since before git history) to fix issues where gcc will optimize
away loads in code that looks 100% correct, but is _technically_ undefined
behavior, and thus can be thrown away by the compiler.

E.g. arm64's vPMU counter access test casts a uint64_t (unsigned long)
pointer to a u64 (unsigned long long) pointer when setting PMCR.N via
u64p_replace_bits(), which gcc-13 detects and optimizes away, i.e. ignores
the result and uses the original PMCR.

The issue is most easily observed by making set_pmcr_n() noinline and
wrapping the call with printf(), e.g. sans comments, for this code:

  printf("orig = %lx, next = %lx, want = %lu\n", pmcr_orig, pmcr, pmcr_n);
  set_pmcr_n(&pmcr, pmcr_n);
  printf("orig = %lx, next = %lx, want = %lu\n", pmcr_orig, pmcr, pmcr_n);

gcc-13 generates:

 0000000000401c90 <set_pmcr_n>:
  401c90:       f9400002        ldr     x2, [x0]
  401c94:       b3751022        bfi     x2, x1, ChimeraOS#11, ChimeraOS#5
  401c98:       f9000002        str     x2, [x0]
  401c9c:       d65f03c0        ret

 0000000000402660 <test_create_vpmu_vm_with_pmcr_n>:
  402724:       aa1403e3        mov     x3, x20
  402728:       aa1503e2        mov     x2, x21
  40272c:       aa1603e0        mov     x0, x22
  402730:       aa1503e1        mov     x1, x21
  402734:       940060ff        bl      41ab30 <_IO_printf>
  402738:       aa1403e1        mov     x1, x20
  40273c:       910183e0        add     x0, sp, #0x60
  402740:       97fffd54        bl      401c90 <set_pmcr_n>
  402744:       aa1403e3        mov     x3, x20
  402748:       aa1503e2        mov     x2, x21
  40274c:       aa1503e1        mov     x1, x21
  402750:       aa1603e0        mov     x0, x22
  402754:       940060f7        bl      41ab30 <_IO_printf>

with the value stored in [sp + 0x60] ignored by both printf() above and
in the test proper, resulting in a false failure due to vcpu_set_reg()
simply storing the original value, not the intended value.

  $ ./vpmu_counter_access
  Random seed: 0x6b8b4567
  orig = 3040, next = 3040, want = 0
  orig = 3040, next = 3040, want = 0
  ==== Test Assertion Failure ====
    aarch64/vpmu_counter_access.c:505: pmcr_n == get_pmcr_n(pmcr)
    pid=71578 tid=71578 errno=9 - Bad file descriptor
       1        0x400673: run_access_test at vpmu_counter_access.c:522
       2         (inlined by) main at vpmu_counter_access.c:643
       3        0x4132d7: __libc_start_call_main at libc-start.o:0
       4        0x413653: __libc_start_main at ??:0
       5        0x40106f: _start at ??:0
    Failed to update PMCR.N to 0 (received: 6)

Somewhat bizarrely, gcc-11 also exhibits the same behavior, but only if
set_pmcr_n() is marked noinline, whereas gcc-13 fails even if set_pmcr_n()
is inlined in its sole caller.

Cc: stable@vger.kernel.org
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116912
Signed-off-by: Sean Christopherson <seanjc@google.com>
flukejones pushed a commit to flukejones/linux that referenced this pull request Dec 5, 2024
[ Upstream commit 5bf1557 ]

test_progs uses glibc specific functions backtrace() and
backtrace_symbols_fd() to print backtrace in case of SIGSEGV.

Recent commit (see fixes) updated test_progs.c to define stub versions
of the same functions with attriubte "weak" in order to allow linking
test_progs against musl libc. Unfortunately this broke the backtrace
handling for glibc builds.

As it turns out, glibc defines backtrace() and backtrace_symbols_fd()
as weak:

  $ llvm-readelf --symbols /lib64/libc.so.6 \
     | grep -P '( backtrace_symbols_fd| backtrace)$'
  4910: 0000000000126b40   161 FUNC    WEAK   DEFAULT    16 backtrace
  6843: 0000000000126f90   852 FUNC    WEAK   DEFAULT    16 backtrace_symbols_fd

So does test_progs:

 $ llvm-readelf --symbols test_progs \
    | grep -P '( backtrace_symbols_fd| backtrace)$'
  2891: 00000000006ad190    15 FUNC    WEAK   DEFAULT    13 backtrace
 11215: 00000000006ad1a0    41 FUNC    WEAK   DEFAULT    13 backtrace_symbols_fd

In such situation dynamic linker is not obliged to favour glibc
implementation over the one defined in test_progs.

Compiling with the following simple modification to test_progs.c
demonstrates the issue:

  $ git diff
  ...
  \--- a/tools/testing/selftests/bpf/test_progs.c
  \+++ b/tools/testing/selftests/bpf/test_progs.c
  \@@ -1817,6 +1817,7 @@ int main(int argc, char **argv)
          if (err)
                  return err;

  +       *(int *)0xdeadbeef  = 42;
          err = cd_flavor_subdir(argv[0]);
          if (err)
                  return err;

  $ ./test_progs
  [0]: Caught signal ChimeraOS#11!
  Stack trace:
  <backtrace not supported>
  Segmentation fault (core dumped)

Resolve this by hiding stub definitions behind __GLIBC__ macro check
instead of using "weak" attribute.

Fixes: c9a83e7 ("selftests/bpf: Fix compile if backtrace support missing in libc")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Tony Ambardar <tony.ambardar@gmail.com>
Reviewed-by: Tony Ambardar <tony.ambardar@gmail.com>
Acked-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/bpf/20241003210307.3847907-1-eddyz87@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
flukejones pushed a commit to flukejones/linux that referenced this pull request Dec 5, 2024
commit 5b188cc upstream.

Disable strict aliasing, as has been done in the kernel proper for decades
(literally since before git history) to fix issues where gcc will optimize
away loads in code that looks 100% correct, but is _technically_ undefined
behavior, and thus can be thrown away by the compiler.

E.g. arm64's vPMU counter access test casts a uint64_t (unsigned long)
pointer to a u64 (unsigned long long) pointer when setting PMCR.N via
u64p_replace_bits(), which gcc-13 detects and optimizes away, i.e. ignores
the result and uses the original PMCR.

The issue is most easily observed by making set_pmcr_n() noinline and
wrapping the call with printf(), e.g. sans comments, for this code:

  printf("orig = %lx, next = %lx, want = %lu\n", pmcr_orig, pmcr, pmcr_n);
  set_pmcr_n(&pmcr, pmcr_n);
  printf("orig = %lx, next = %lx, want = %lu\n", pmcr_orig, pmcr, pmcr_n);

gcc-13 generates:

 0000000000401c90 <set_pmcr_n>:
  401c90:       f9400002        ldr     x2, [x0]
  401c94:       b3751022        bfi     x2, x1, ChimeraOS#11, ChimeraOS#5
  401c98:       f9000002        str     x2, [x0]
  401c9c:       d65f03c0        ret

 0000000000402660 <test_create_vpmu_vm_with_pmcr_n>:
  402724:       aa1403e3        mov     x3, x20
  402728:       aa1503e2        mov     x2, x21
  40272c:       aa1603e0        mov     x0, x22
  402730:       aa1503e1        mov     x1, x21
  402734:       940060ff        bl      41ab30 <_IO_printf>
  402738:       aa1403e1        mov     x1, x20
  40273c:       910183e0        add     x0, sp, #0x60
  402740:       97fffd54        bl      401c90 <set_pmcr_n>
  402744:       aa1403e3        mov     x3, x20
  402748:       aa1503e2        mov     x2, x21
  40274c:       aa1503e1        mov     x1, x21
  402750:       aa1603e0        mov     x0, x22
  402754:       940060f7        bl      41ab30 <_IO_printf>

with the value stored in [sp + 0x60] ignored by both printf() above and
in the test proper, resulting in a false failure due to vcpu_set_reg()
simply storing the original value, not the intended value.

  $ ./vpmu_counter_access
  Random seed: 0x6b8b4567
  orig = 3040, next = 3040, want = 0
  orig = 3040, next = 3040, want = 0
  ==== Test Assertion Failure ====
    aarch64/vpmu_counter_access.c:505: pmcr_n == get_pmcr_n(pmcr)
    pid=71578 tid=71578 errno=9 - Bad file descriptor
       1        0x400673: run_access_test at vpmu_counter_access.c:522
       2         (inlined by) main at vpmu_counter_access.c:643
       3        0x4132d7: __libc_start_call_main at libc-start.o:0
       4        0x413653: __libc_start_main at ??:0
       5        0x40106f: _start at ??:0
    Failed to update PMCR.N to 0 (received: 6)

Somewhat bizarrely, gcc-11 also exhibits the same behavior, but only if
set_pmcr_n() is marked noinline, whereas gcc-13 fails even if set_pmcr_n()
is inlined in its sole caller.

Cc: stable@vger.kernel.org
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116912
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
flukejones pushed a commit to flukejones/linux that referenced this pull request Dec 5, 2024
[ Upstream commit 5bf1557 ]

test_progs uses glibc specific functions backtrace() and
backtrace_symbols_fd() to print backtrace in case of SIGSEGV.

Recent commit (see fixes) updated test_progs.c to define stub versions
of the same functions with attriubte "weak" in order to allow linking
test_progs against musl libc. Unfortunately this broke the backtrace
handling for glibc builds.

As it turns out, glibc defines backtrace() and backtrace_symbols_fd()
as weak:

  $ llvm-readelf --symbols /lib64/libc.so.6 \
     | grep -P '( backtrace_symbols_fd| backtrace)$'
  4910: 0000000000126b40   161 FUNC    WEAK   DEFAULT    16 backtrace
  6843: 0000000000126f90   852 FUNC    WEAK   DEFAULT    16 backtrace_symbols_fd

So does test_progs:

 $ llvm-readelf --symbols test_progs \
    | grep -P '( backtrace_symbols_fd| backtrace)$'
  2891: 00000000006ad190    15 FUNC    WEAK   DEFAULT    13 backtrace
 11215: 00000000006ad1a0    41 FUNC    WEAK   DEFAULT    13 backtrace_symbols_fd

In such situation dynamic linker is not obliged to favour glibc
implementation over the one defined in test_progs.

Compiling with the following simple modification to test_progs.c
demonstrates the issue:

  $ git diff
  ...
  \--- a/tools/testing/selftests/bpf/test_progs.c
  \+++ b/tools/testing/selftests/bpf/test_progs.c
  \@@ -1817,6 +1817,7 @@ int main(int argc, char **argv)
          if (err)
                  return err;

  +       *(int *)0xdeadbeef  = 42;
          err = cd_flavor_subdir(argv[0]);
          if (err)
                  return err;

  $ ./test_progs
  [0]: Caught signal ChimeraOS#11!
  Stack trace:
  <backtrace not supported>
  Segmentation fault (core dumped)

Resolve this by hiding stub definitions behind __GLIBC__ macro check
instead of using "weak" attribute.

Fixes: c9a83e7 ("selftests/bpf: Fix compile if backtrace support missing in libc")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Tony Ambardar <tony.ambardar@gmail.com>
Reviewed-by: Tony Ambardar <tony.ambardar@gmail.com>
Acked-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/bpf/20241003210307.3847907-1-eddyz87@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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