CVE-2026-45904
powerpc/eeh: fix recursive pci_lock_rescan_remove locking in EEH event handling
In the Linux kernel, the following vulnerability has been resolved: powerpc/eeh: fix recursive pci_lock_rescan_remove locking in EEH event handling The recent commit 1010b4c012b0 ("powerpc/eeh: Make EEH driver device hotplug safe") restructured the EEH driver to improve synchronization with the PCI hotplug layer. However, it inadvertently moved pci_lock_rescan_remove() outside its intended scope in eeh_handle_normal_event(), leading to broken PCI error reporting and improper EEH event triggering. Specifically, eeh_handle_normal_event() acquired pci_lock_rescan_remove() before calling eeh_pe_bus_get(), but eeh_pe_bus_get() itself attempts to acquire the same lock internally, causing nested locking and disrupting normal EEH event handling paths. This patch adds a boolean parameter do_lock to _eeh_pe_bus_get(), with two public wrappers: eeh_pe_bus_get() with locking enabled. eeh_pe_bus_get_nolock() that skips locking. Callers that already hold pci_lock_rescan_remove() now use eeh_pe_bus_get_nolock() to avoid recursive lock acquisition. Additionally, pci_lock_rescan_remove() calls are restored to the correct position—after eeh_pe_bus_get() and immediately before iterating affected PEs and devices. This ensures EEH-triggered PCI removes occur under proper bus rescan locking without recursive lock contention. The eeh_pe_loc_get() function has been split into two functions: eeh_pe_loc_get(struct eeh_pe *pe) which retrieves the loc for given PE. eeh_pe_loc_get_bus(struct pci_bus *bus) which retrieves the location code for given bus. This resolves lockdep warnings such as: <snip> [ 84.964298] [ T928] ============================================ [ 84.964304] [ T928] WARNING: possible recursive locking detected [ 84.964311] [ T928] 6.18.0-rc3 #51 Not tainted [ 84.964315] [ T928] -------------------------------------------- [ 84.964320] [ T928] eehd/928 is trying to acquire lock: [ 84.964324] [ T928] c000000003b29d58 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pci_lock_rescan_remove+0x28/0x40 [ 84.964342] [ T928] but task is already holding lock: [ 84.964347] [ T928] c000000003b29d58 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pci_lock_rescan_remove+0x28/0x40 [ 84.964357] [ T928] other info that might help us debug this: [ 84.964363] [ T928] Possible unsafe locking scenario: [ 84.964367] [ T928] CPU0 [ 84.964370] [ T928] ---- [ 84.964373] [ T928] lock(pci_rescan_remove_lock); [ 84.964378] [ T928] lock(pci_rescan_remove_lock); [ 84.964383] [ T928] *** DEADLOCK *** [ 84.964388] [ T928] May be due to missing lock nesting notation [ 84.964393] [ T928] 1 lock held by eehd/928: [ 84.964397] [ T928] #0: c000000003b29d58 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pci_lock_rescan_remove+0x28/0x40 [ 84.964408] [ T928] stack backtrace: [ 84.964414] [ T928] CPU: 2 UID: 0 PID: 928 Comm: eehd Not tainted 6.18.0-rc3 #51 VOLUNTARY [ 84.964417] [ T928] Hardware name: IBM,9080-HEX POWER10 (architected) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_022) hv:phyp pSeries [ 84.964419] [ T928] Call Trace: [ 84.964420] [ T928] [c0000011a7157990] [c000000001705de4] dump_stack_lvl+0xc8/0x130 (unreliable) [ 84.964424] [ T928] [c0000011a71579d0] [c0000000002f66e0] print_deadlock_bug+0x430/0x440 [ 84.964428] [ T928] [c0000011a7157a70] [c0000000002fd0c0] __lock_acquire+0x1530/0x2d80 [ 84.964431] [ T928] [c0000011a7157ba0] [c0000000002fea54] lock_acquire+0x144/0x410 [ 84.964433] [ T928] [c0000011a7157cb0] [c0000011a7157cb0] __mutex_lock+0xf4/0x1050 [ 84.964436] [ T928] [c0000011a7157e00] [c000000000de21d8] pci_lock_rescan_remove+0x28/0x40 [ 84.964439] [ T928] [c0000011a7157e20] [c00000000004ed98] eeh_pe_bus_get+0x48/0xc0 [ 84.964442] [ T928] [c0000011a7157e50] [c00000 ---truncated---
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| Linux Linux |
≥ 502f08831a9afb72dc98a56ae6504da43e93b250; < 89810e2d80281d42f855fac813786758ee16e323 (affected, git) ≥ f56e004b781719d8fdf6c9619b15caf2579bc1f2; < 788dd28fd49610d6047cbb15dbf1186afffdfbaf (affected, git) ≥ 59c6d3d81d42bf543c90597b4f38c53d6874c5a1; < f49faa4a64f8ac0e38983e606075b25dfcfc9ad4 (affected, git) ≥ a426e8a6ae161f51888585b065db0f8f93ab2e16; < 87a1f93986aa1500b85aeff16b0b71c29ea116ea (affected, git) ≥ d2c60a8a387e9fcc28447ef36c03f8e49fd052a6; < f8b16d5764ee1e78c1ef333017ad383ffe76fcdc (affected, git) ≥ 1010b4c012b0d78dfb9d3132b49aa2ef024a07a7; < 6e6561231c6cfc32c5631aeecc0928ff2b14265c (affected, git) ≥ 1010b4c012b0d78dfb9d3132b49aa2ef024a07a7; < b85ee287bfe52c6b2d9b41758b5e0d08679d5b39 (affected, git) ≥ 1010b4c012b0d78dfb9d3132b49aa2ef024a07a7; < 815a8d2feb5615ae7f0b5befd206af0b0160614c (affected, git) d42bbd8f30ac38b1ce54715bf08ec3dac18d6b25 (affected, git) 19d5036e7ad766cf212aebec23b9f1d7924a62bc (affected, git) ≥ 5.10.241; < 5.10.252 (affected, semver) ≥ 5.15.190; < 5.15.202 (affected, semver) ≥ 6.1.148; < 6.1.165 (affected, semver) ≥ 6.6.102; < 6.6.128 (affected, semver) ≥ 6.12.42; < 6.12.75 (affected, semver) ≥ 6.15.10; < 6.16 (affected, semver) ≥ 6.16.1; < 6.17 (affected, semver) Other versions: unaffected |
CNA: Linux |
| Linux Linux |
6.17 (affected) ≥ 0; < 6.17 (unaffected, semver) ≥ 5.10.252; ≤ 5.10.* (unaffected, semver) ≥ 5.15.202; ≤ 5.15.* (unaffected, semver) ≥ 6.1.165; ≤ 6.1.* (unaffected, semver) ≥ 6.6.128; ≤ 6.6.* (unaffected, semver) ≥ 6.12.75; ≤ 6.12.* (unaffected, semver) ≥ 6.18.14; ≤ 6.18.* (unaffected, semver) ≥ 6.19.4; ≤ 6.19.* (unaffected, semver) ≥ 7.0; ≤ * (unaffected, original_commit_for_fix) Other versions: affected |
CNA: Linux |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
No CVSS assessment reported. An unscored record is not a low-severity determination.
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://git.kernel.org/stable/c/89810e2d80281d42f855fac813786758ee16e323CNA: Linux
- https://git.kernel.org/stable/c/788dd28fd49610d6047cbb15dbf1186afffdfbafCNA: Linux
- https://git.kernel.org/stable/c/f49faa4a64f8ac0e38983e606075b25dfcfc9ad4CNA: Linux
- https://git.kernel.org/stable/c/87a1f93986aa1500b85aeff16b0b71c29ea116eaCNA: Linux
- https://git.kernel.org/stable/c/f8b16d5764ee1e78c1ef333017ad383ffe76fcdcCNA: Linux
- https://git.kernel.org/stable/c/6e6561231c6cfc32c5631aeecc0928ff2b14265cCNA: Linux
- https://git.kernel.org/stable/c/b85ee287bfe52c6b2d9b41758b5e0d08679d5b39CNA: Linux
- https://git.kernel.org/stable/c/815a8d2feb5615ae7f0b5befd206af0b0160614cCNA: Linux
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