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Remove wrong sentence about mangling in v0 scheme #136

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merged 1 commit into from
Mar 21, 2021

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@ojeda ojeda commented Mar 21, 2021

@bjorn3 helpfully noted that symbols do not stay the same across
rustc compiler versions.

The overall sentence is anyway a bit misleading, because the "hard"
requirement is the second one: mixing rustc compiler versions
is not something we will support. IIRC I was thinking about possible
patch level fixes to rustc stable versions when I wrote that.

Link: #52 (comment)
Signed-off-by: Miguel Ojeda ojeda@kernel.org

@bjorn3 helpfully noted that symbols do not stay the same across
`rustc` compiler versions.

The overall sentence is anyway a bit misleading, because the "hard"
requirement is the second one: mixing `rustc` compiler versions
is not something we will support. IIRC I was thinking about possible
patch level fixes to `rustc` stable versions when I wrote that.

Link: Rust-for-Linux#52 (comment)
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
@ojeda ojeda merged commit 9445057 into Rust-for-Linux:rust Mar 21, 2021
@ojeda ojeda deleted the misleading branch March 21, 2021 21:53
wedsonaf pushed a commit to wedsonaf/linux that referenced this pull request Jul 11, 2022
Fix our pointer offset usage in error_state_read
when there is no i915_gpu_coredump but buf offset
is non-zero.

This fixes a kernel page fault can happen when
multiple tests are running concurrently in a loop
and one is producing engine resets and consuming
the i915 error_state dump while the other is
forcing full GT resets. (takes a while to trigger).

The dmesg call trace:

[ 5590.803000] BUG: unable to handle page fault for address:
               ffffffffa0b0e000
[ 5590.803009] #PF: supervisor read access in kernel mode
[ 5590.803013] #PF: error_code(0x0000) - not-present page
[ 5590.803016] PGD 5814067 P4D 5814067 PUD 5815063 PMD 109de4067
               PTE 0
[ 5590.803022] Oops: 0000 [Rust-for-Linux#1] PREEMPT SMP NOPTI
[ 5590.803026] CPU: 5 PID: 13656 Comm: i915_hangman Tainted: G U
                    5.17.0-rc5-ups69-guc-err-capt-rev6+ Rust-for-Linux#136
[ 5590.803033] Hardware name: Intel Corporation Alder Lake Client
                    Platform/AlderLake-M LP4x RVP, BIOS ADLPFWI1.R00.
                    3031.A02.2201171222	01/17/2022
[ 5590.803039] RIP: 0010:memcpy_erms+0x6/0x10
[ 5590.803045] Code: fe ff ff cc eb 1e 0f 1f 00 48 89 f8 48 89 d1
                     48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3
                     66 0f 1f 44 00 00 48 89 f8 48 89 d1 <f3> a4
                     c3 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20
                     72 7e 40 38 fe
[ 5590.803054] RSP: 0018:ffffc90003a8fdf0 EFLAGS: 00010282
[ 5590.803057] RAX: ffff888107ee9000 RBX: ffff888108cb1a00
               RCX: 0000000000000f8f
[ 5590.803061] RDX: 0000000000001000 RSI: ffffffffa0b0e000
               RDI: ffff888107ee9071
[ 5590.803065] RBP: 0000000000000000 R08: 0000000000000001
               R09: 0000000000000001
[ 5590.803069] R10: 0000000000000001 R11: 0000000000000002
               R12: 0000000000000019
[ 5590.803073] R13: 0000000000174fff R14: 0000000000001000
               R15: ffff888107ee9000
[ 5590.803077] FS: 00007f62a99bee80(0000) GS:ffff88849f880000(0000)
               knlGS:0000000000000000
[ 5590.803082] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 5590.803085] CR2: ffffffffa0b0e000 CR3: 000000010a1a8004
               CR4: 0000000000770ee0
[ 5590.803089] PKRU: 55555554
[ 5590.803091] Call Trace:
[ 5590.803093] <TASK>
[ 5590.803096] error_state_read+0xa1/0xd0 [i915]
[ 5590.803175] kernfs_fop_read_iter+0xb2/0x1b0
[ 5590.803180] new_sync_read+0x116/0x1a0
[ 5590.803185] vfs_read+0x114/0x1b0
[ 5590.803189] ksys_read+0x63/0xe0
[ 5590.803193] do_syscall_64+0x38/0xc0
[ 5590.803197] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 5590.803201] RIP: 0033:0x7f62aaea5912
[ 5590.803204] Code: c0 e9 b2 fe ff ff 50 48 8d 3d 5a b9 0c 00 e8 05
                     19 02 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25
                     18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff
                     ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24
[ 5590.803213] RSP: 002b:00007fff5b659ae8 EFLAGS: 00000246
               ORIG_RAX: 0000000000000000
[ 5590.803218] RAX: ffffffffffffffda RBX: 0000000000100000
               RCX: 00007f62aaea5912
[ 5590.803221] RDX: 000000000008b000 RSI: 00007f62a8c4000f
               RDI: 0000000000000006
[ 5590.803225] RBP: 00007f62a8bcb00f R08: 0000000000200010
               R09: 0000000000101000
[ 5590.803229] R10: 0000000000000001 R11: 0000000000000246
               R12: 0000000000000006
[ 5590.803233] R13: 0000000000075000 R14: 00007f62a8acb010
               R15: 0000000000200000
[ 5590.803238] </TASK>
[ 5590.803240] Modules linked in: i915 ttm drm_buddy drm_dp_helper
                        drm_kms_helper syscopyarea sysfillrect sysimgblt
                        fb_sys_fops prime_numbers nfnetlink br_netfilter
                        overlay mei_pxp mei_hdcp x86_pkg_temp_thermal
                        coretemp kvm_intel snd_hda_codec_hdmi snd_hda_intel
                        snd_intel_dspcfg snd_hda_codec snd_hwdep
                        snd_hda_core snd_pcm mei_me mei fuse ip_tables
                        x_tables crct10dif_pclmul e1000e crc32_pclmul ptp
                        i2c_i801 ghash_clmulni_intel i2c_smbus pps_core
                        [last unloa ded: ttm]
[ 5590.803277] CR2: ffffffffa0b0e000
[ 5590.803280] ---[ end trace 0000000000000000 ]---

Fixes: 0e39037 ("drm/i915: Cache the error string")
Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220311004311.514198-2-alan.previn.teres.alexis@intel.com
(cherry picked from commit 3304033)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
fbq pushed a commit that referenced this pull request Sep 25, 2023
Inject fault while probing kunit-example-test.ko, if kstrdup()
fails in mod_sysfs_setup() in load_module(), the mod->state will
switch from MODULE_STATE_COMING to MODULE_STATE_GOING instead of
from MODULE_STATE_LIVE to MODULE_STATE_GOING, so only
kunit_module_exit() will be called without kunit_module_init(), and
the mod->kunit_suites is no set correctly and the free in
kunit_free_suite_set() will cause below wild-memory-access bug.

The mod->state state machine when load_module() succeeds:

MODULE_STATE_UNFORMED ---> MODULE_STATE_COMING ---> MODULE_STATE_LIVE
	 ^						|
	 |						| delete_module
	 +---------------- MODULE_STATE_GOING <---------+

The mod->state state machine when load_module() fails at
mod_sysfs_setup():

MODULE_STATE_UNFORMED ---> MODULE_STATE_COMING ---> MODULE_STATE_GOING
	^						|
	|						|
	+-----------------------------------------------+

Call kunit_module_init() at MODULE_STATE_COMING state to fix the issue
because MODULE_STATE_LIVE is transformed from it.

 Unable to handle kernel paging request at virtual address ffffff341e942a88
 KASAN: maybe wild-memory-access in range [0x0003f9a0f4a15440-0x0003f9a0f4a15447]
 Mem abort info:
   ESR = 0x0000000096000004
   EC = 0x25: DABT (current EL), IL = 32 bits
   SET = 0, FnV = 0
   EA = 0, S1PTW = 0
   FSC = 0x04: level 0 translation fault
 Data abort info:
   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
 swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000441ea000
 [ffffff341e942a88] pgd=0000000000000000, p4d=0000000000000000
 Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
 Modules linked in: kunit_example_test(-) cfg80211 rfkill 8021q garp mrp stp llc ipv6 [last unloaded: kunit_example_test]
 CPU: 3 PID: 2035 Comm: modprobe Tainted: G        W        N 6.5.0-next-20230828+ #136
 Hardware name: linux,dummy-virt (DT)
 pstate: a0000005 (NzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : kfree+0x2c/0x70
 lr : kunit_free_suite_set+0xcc/0x13c
 sp : ffff8000829b75b0
 x29: ffff8000829b75b0 x28: ffff8000829b7b90 x27: 0000000000000000
 x26: dfff800000000000 x25: ffffcd07c82a7280 x24: ffffcd07a50ab300
 x23: ffffcd07a50ab2e8 x22: 1ffff00010536ec0 x21: dfff800000000000
 x20: ffffcd07a50ab2f0 x19: ffffcd07a50ab2f0 x18: 0000000000000000
 x17: 0000000000000000 x16: 0000000000000000 x15: ffffcd07c24b6764
 x14: ffffcd07c24b63c0 x13: ffffcd07c4cebb94 x12: ffff700010536ec7
 x11: 1ffff00010536ec6 x10: ffff700010536ec6 x9 : dfff800000000000
 x8 : 00008fffefac913a x7 : 0000000041b58ab3 x6 : 0000000000000000
 x5 : 1ffff00010536ec5 x4 : ffff8000829b7628 x3 : dfff800000000000
 x2 : ffffff341e942a80 x1 : ffffcd07a50aa000 x0 : fffffc0000000000
 Call trace:
  kfree+0x2c/0x70
  kunit_free_suite_set+0xcc/0x13c
  kunit_module_notify+0xd8/0x360
  blocking_notifier_call_chain+0xc4/0x128
  load_module+0x382c/0x44a4
  init_module_from_file+0xd4/0x128
  idempotent_init_module+0x2c8/0x524
  __arm64_sys_finit_module+0xac/0x100
  invoke_syscall+0x6c/0x258
  el0_svc_common.constprop.0+0x160/0x22c
  do_el0_svc+0x44/0x5c
  el0_svc+0x38/0x78
  el0t_64_sync_handler+0x13c/0x158
  el0t_64_sync+0x190/0x194
 Code: aa0003e1 b25657e0 d34cfc42 8b021802 (f9400440)
 ---[ end trace 0000000000000000 ]---
 Kernel panic - not syncing: Oops: Fatal exception
 SMP: stopping secondary CPUs
 Kernel Offset: 0x4d0742200000 from 0xffff800080000000
 PHYS_OFFSET: 0xffffee43c0000000
 CPU features: 0x88000203,3c020000,1000421b
 Memory Limit: none
 Rebooting in 1 seconds..

Fixes: 3d6e446 ("kunit: unify module and builtin suite definitions")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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