CVE-2024-35795

medium

Published 2024-11-12 · Modified 2024-11-12

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CVSS v3

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CVSS v4 NEW

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not yet in upstream

VIR risk

5.5

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: fix deadlock while reading mqd from debugfs An errant disk backup on my desktop got into debugfs and triggered the following deadlock scenario in the amdgpu debugfs files. The machine also hard-resets immediately after those lines are printed (although I wasn't able to reproduce that part when reading by hand): [ 1318.016074][ T1082] ====================================================== [ 1318.016607][ T1082] WARNING: possible circular locking dependency detected [ 1318.017107][ T1082] 6.8.0-rc7-00015-ge0c8221b72c0 #17 Not tainted [ 1318.017598][ T1082] ------------------------------------------------------ [ 1318.018096][ T1082] tar/1082 is trying to acquire lock: [ 1318.018585][ T1082] ffff98c44175d6a0 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x40/0x80 [ 1318.019084][ T1082] [ 1318.019084][ T1082] but task is already holding lock: [ 1318.020052][ T1082] ffff98c4c13f55f8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: amdgpu_debugfs_mqd_read+0x6a/0x250 [amdgpu] [ 1318.020607][ T1082] [ 1318.020607][ T1082] which lock already depends on the new lock. [ 1318.020607][ T1082] [ 1318.022081][ T1082] [ 1318.022081][ T1082] the existing dependency chain (in reverse order) is: [ 1318.023083][ T1082] [ 1318.023083][ T1082] -> #2 (reservation_ww_class_mutex){+.+.}-{3:3}: [ 1318.024114][ T1082] __ww_mutex_lock.constprop.0+0xe0/0x12f0 [ 1318.024639][ T1082] ww_mutex_lock+0x32/0x90 [ 1318.025161][ T1082] dma_resv_lockdep+0x18a/0x330 [ 1318.025683][ T1082] do_one_initcall+0x6a/0x350 [ 1318.026210][ T1082] kernel_init_freeable+0x1a3/0x310 [ 1318.026728][ T1082] kernel_init+0x15/0x1a0 [ 1318.027242][ T1082] ret_from_fork+0x2c/0x40 [ 1318.027759][ T1082] ret_from_fork_asm+0x11/0x20 [ 1318.028281][ T1082] [ 1318.028281][ T1082] -> #1 (reservation_ww_class_acquire){+.+.}-{0:0}: [ 1318.029297][ T1082] dma_resv_lockdep+0x16c/0x330 [ 1318.029790][ T1082] do_one_initcall+0x6a/0x350 [ 1318.030263][ T1082] kernel_init_freeable+0x1a3/0x310 [ 1318.030722][ T1082] kernel_init+0x15/0x1a0 [ 1318.031168][ T1082] ret_from_fork+0x2c/0x40 [ 1318.031598][ T1082] ret_from_fork_asm+0x11/0x20 [ 1318.032011][ T1082] [ 1318.032011][ T1082] -> #0 (&mm->mmap_lock){++++}-{3:3}: [ 1318.032778][ T1082] __lock_acquire+0x14bf/0x2680 [ 1318.033141][ T1082] lock_acquire+0xcd/0x2c0 [ 1318.033487][ T1082] __might_fault+0x58/0x80 [ 1318.033814][ T1082] amdgpu_debugfs_mqd_read+0x103/0x250 [amdgpu] [ 1318.034181][ T1082] full_proxy_read+0x55/0x80 [ 1318.034487][ T1082] vfs_read+0xa7/0x360 [ 1318.034788][ T1082] ksys_read+0x70/0xf0 [ 1318.035085][ T1082] do_syscall_64+0x94/0x180 [ 1318.035375][ T1082] entry_SYSCALL_64_after_hwframe+0x46/0x4e [ 1318.035664][ T1082] [ 1318.035664][ T1082] other info that might help us debug this: [ 1318.035664][ T1082] [ 1318.036487][ T1082] Chain exists of: [ 1318.036487][ T1082] &mm->mmap_lock --> reservation_ww_class_acquire --> reservation_ww_class_mutex [ 1318.036487][ T1082] [ 1318.037310][ T1082] Possible unsafe locking scenario: [ 1318.037310][ T1082] [ 1318.037838][ T1082] CPU0 CPU1 [ 1318.038101][ T1082] ---- ---- [ 1318.038350][ T1082] lock(reservation_ww_class_mutex); [ 1318.038590][ T1082] lock(reservation_ww_class_acquire); [ 1318.038839][ T1082] lock(reservation_ww_class_mutex); [ 1318.039083][ T1082] rlock(&mm->mmap_lock); [ 1318.039328][ T1082] [ 1318.039328][ T1082] *** DEADLOCK *** [ 1318.039328][ T1082] [ 1318.040029][ T1082] 1 lock held by tar/1082: [ 1318.040259][ T1082] #0: ffff98c4c13f55f8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: amdgpu_debugfs_mqd_read+0x6a/0x250 [amdgpu] [ 1318.040560][ T1082] [ 1318.040560][ T1082] stack backtrace: [ ---truncated---

Predictions

Exploit likelihood

20%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

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OS impact

OS	Version	Status	Fixed in
rhel	9	fixed
sles		affected
debian	bookworm	fixed	`0`
debian	bullseye	fixed	`0`
debian	forky	fixed	`6.7.12-1`
debian	sid	fixed	`6.7.12-1`
debian	trixie	fixed	`6.7.12-1`

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.