{"cve":"CVE-2026-45904","nvd":{"published":"2026-05-27T14:17:04.820","modified":"2026-06-24T16:28:46.760","status":"Undergoing Analysis","description":"In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/eeh: fix recursive pci_lock_rescan_remove locking in EEH event handling\n\nThe recent commit 1010b4c012b0 (\"powerpc/eeh: Make EEH driver device\nhotplug safe\") restructured the EEH driver to improve synchronization\nwith the PCI hotplug layer.\n\nHowever, it inadvertently moved pci_lock_rescan_remove() outside its\nintended scope in eeh_handle_normal_event(), leading to broken PCI\nerror reporting and improper EEH event triggering. Specifically,\neeh_handle_normal_event() acquired pci_lock_rescan_remove() before\ncalling eeh_pe_bus_get(), but eeh_pe_bus_get() itself attempts to\nacquire the same lock internally, causing nested locking and disrupting\nnormal EEH event handling paths.\n\nThis patch adds a boolean parameter do_lock to _eeh_pe_bus_get(),\nwith two public wrappers:\n    eeh_pe_bus_get() with locking enabled.\n    eeh_pe_bus_get_nolock() that skips locking.\n\nCallers that already hold pci_lock_rescan_remove() now use\neeh_pe_bus_get_nolock() to avoid recursive lock acquisition.\n\nAdditionally, pci_lock_rescan_remove() calls are restored to the correct\nposition—after eeh_pe_bus_get() and immediately before iterating affected\nPEs and devices. This ensures EEH-triggered PCI removes occur under proper\nbus rescan locking without recursive lock contention.\n\nThe eeh_pe_loc_get() function has been split into two functions:\n    eeh_pe_loc_get(struct eeh_pe *pe) which retrieves the loc for given PE.\n    eeh_pe_loc_get_bus(struct pci_bus *bus) which retrieves the location\n    code for given bus.\n\nThis resolves lockdep warnings such as:\n<snip>\n[   84.964298] [    T928] ============================================\n[   84.964304] [    T928] WARNING: possible recursive locking detected\n[   84.964311] [    T928] 6.18.0-rc3 #51 Not tainted\n[   84.964315] [    T928] --------------------------------------------\n[   84.964320] [    T928] eehd/928 is trying to acquire lock:\n[   84.964324] [    T928] c000000003b29d58 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pci_lock_rescan_remove+0x28/0x40\n[   84.964342] [    T928]\n                       but task is already holding lock:\n[   84.964347] [    T928] c000000003b29d58 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pci_lock_rescan_remove+0x28/0x40\n[   84.964357] [    T928]\n                       other info that might help us debug this:\n[   84.964363] [    T928]  Possible unsafe locking scenario:\n\n[   84.964367] [    T928]        CPU0\n[   84.964370] [    T928]        ----\n[   84.964373] [    T928]   lock(pci_rescan_remove_lock);\n[   84.964378] [    T928]   lock(pci_rescan_remove_lock);\n[   84.964383] [    T928]\n                       *** DEADLOCK ***\n\n[   84.964388] [    T928]  May be due to missing lock nesting notation\n\n[   84.964393] [    T928] 1 lock held by eehd/928:\n[   84.964397] [    T928]  #0: c000000003b29d58 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pci_lock_rescan_remove+0x28/0x40\n[   84.964408] [    T928]\n                       stack backtrace:\n[   84.964414] [    T928] CPU: 2 UID: 0 PID: 928 Comm: eehd Not tainted 6.18.0-rc3 #51 VOLUNTARY\n[   84.964417] [    T928] Hardware name: IBM,9080-HEX POWER10 (architected) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_022) hv:phyp pSeries\n[   84.964419] [    T928] Call Trace:\n[   84.964420] [    T928] [c0000011a7157990] [c000000001705de4] dump_stack_lvl+0xc8/0x130 (unreliable)\n[   84.964424] [    T928] [c0000011a71579d0] [c0000000002f66e0] print_deadlock_bug+0x430/0x440\n[   84.964428] [    T928] [c0000011a7157a70] [c0000000002fd0c0] __lock_acquire+0x1530/0x2d80\n[   84.964431] [    T928] [c0000011a7157ba0] [c0000000002fea54] lock_acquire+0x144/0x410\n[   84.964433] [    T928] [c0000011a7157cb0] [c0000011a7157cb0] __mutex_lock+0xf4/0x1050\n[   84.964436] [    T928] [c0000011a7157e00] [c000000000de21d8] pci_lock_rescan_remove+0x28/0x40\n[   84.964439] [    T928] [c0000011a7157e20] [c00000000004ed98] eeh_pe_bus_get+0x48/0xc0\n[   84.964442] [    T928] [c0000011a7157e50] [c00000\n---truncated---","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-674"],"references":["https://git.kernel.org/stable/c/6e6561231c6cfc32c5631aeecc0928ff2b14265c","https://git.kernel.org/stable/c/788dd28fd49610d6047cbb15dbf1186afffdfbaf","https://git.kernel.org/stable/c/815a8d2feb5615ae7f0b5befd206af0b0160614c","https://git.kernel.org/stable/c/87a1f93986aa1500b85aeff16b0b71c29ea116ea","https://git.kernel.org/stable/c/89810e2d80281d42f855fac813786758ee16e323"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:36:28.938604137+00:00"},"epss":{"cve":"CVE-2026-45904","score":0.0016,"percentile":0.05211,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}