{"cve":"CVE-2026-64100","nvd":{"published":"2026-07-19T16:17:51.140","modified":"2026-08-11T16:04:37.380","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/msm: Fix shrinker deadlock\n\nWith PROVE_LOCKING on an Snapdragon X1 and VM reclaim pressure, we see:\n\n   ======================================================\n   WARNING: possible circular locking dependency detected\n   7.0.0-debug+ #43 Tainted: G        W\n   ------------------------------------------------------\n   kswapd0/82 is trying to acquire lock:\n   ffff800080ec3870 (reservation_ww_class_acquire){+.+.}-{0:0}, at: msm_gem_shrinker_scan+0x17c/0x400 [msm]\n\n   but task is already holding lock:\n   ffffc31709b263b8 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x88/0x988\n\n   which lock already depends on the new lock.\n\n   the existing dependency chain (in reverse order) is:\n\n   -> #2 (fs_reclaim){+.+.}-{0:0}:\n          __lock_acquire+0x4d0/0xad0\n          lock_acquire.part.0+0xc4/0x248\n          lock_acquire+0x8c/0x248\n          fs_reclaim_acquire+0xd0/0xf0\n          dma_resv_lockdep+0x224/0x348\n          do_one_initcall+0x84/0x5d0\n          do_initcalls+0x194/0x1d8\n          kernel_init_freeable+0x128/0x180\n          kernel_init+0x2c/0x160\n          ret_from_fork+0x10/0x20\n\n   -> #1 (reservation_ww_class_mutex){+.+.}-{4:4}:\n          __lock_acquire+0x4d0/0xad0\n          lock_acquire.part.0+0xc4/0x248\n          lock_acquire+0x8c/0x248\n          dma_resv_lockdep+0x1a8/0x348\n          do_one_initcall+0x84/0x5d0\n          do_initcalls+0x194/0x1d8\n          kernel_init_freeable+0x128/0x180\n          kernel_init+0x2c/0x160\n          ret_from_fork+0x10/0x20\n\n   -> #0 (reservation_ww_class_acquire){+.+.}-{0:0}:\n          check_prev_add+0x114/0x790\n          validate_chain+0x594/0x6f0\n          __lock_acquire+0x4d0/0xad0\n          lock_acquire.part.0+0xc4/0x248\n          lock_acquire+0x8c/0x248\n          drm_gem_lru_scan+0x1ac/0x440\n          msm_gem_shrinker_scan+0x17c/0x400 [msm]\n          do_shrink_slab+0x150/0x4a0\n          shrink_slab+0x144/0x460\n          shrink_one+0x9c/0x1b0\n          shrink_many+0x27c/0x5c0\n          shrink_node+0x344/0x550\n          balance_pgdat+0x2c0/0x988\n          kswapd+0x11c/0x318\n          kthread+0x10c/0x128\n          ret_from_fork+0x10/0x20\n\n   other info that might help us debug this:\n   Chain exists of:\n     reservation_ww_class_acquire --> reservation_ww_class_mutex --> fs_reclaim\n    Possible unsafe locking scenario:\n          CPU0                    CPU1\n          ----                    ----\n     lock(fs_reclaim);\n                                  lock(reservation_ww_class_mutex);\n                                  lock(fs_reclaim);\n     lock(reservation_ww_class_acquire);\n\n    *** DEADLOCK ***\n   1 lock held by kswapd0/82:\n    #0: ffffc31709b263b8 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x88/0x988\n\n   stack backtrace:\n   CPU: 4 UID: 0 PID: 82 Comm: kswapd0 Tainted: G        W           7.0.0-debug+ #43 PREEMPT(full)\n   Tainted: [W]=WARN\n   Hardware name: LENOVO 21BX0016US/21BX0016US, BIOS N3HET94W (1.66 ) 09/15/2025\n   Call trace:\n    show_stack+0x20/0x40 (C)\n    dump_stack_lvl+0x9c/0xd0\n    dump_stack+0x18/0x30\n    print_circular_bug+0x114/0x120\n    check_noncircular+0x178/0x198\n    check_prev_add+0x114/0x790\n    validate_chain+0x594/0x6f0\n    __lock_acquire+0x4d0/0xad0\n    lock_acquire.part.0+0xc4/0x248\n    lock_acquire+0x8c/0x248\n    drm_gem_lru_scan+0x1ac/0x440\n    msm_gem_shrinker_scan+0x17c/0x400 [msm]\n    do_shrink_slab+0x150/0x4a0\n    shrink_slab+0x144/0x460\n    shrink_one+0x9c/0x1b0\n    shrink_many+0x27c/0x5c0\n    shrink_node+0x344/0x550\n    balance_pgdat+0x2c0/0x988\n    kswapd+0x11c/0x318\n    kthread+0x10c/0x128\n    ret_from_fork+0x10/0x20\n\nkswapd0 holding fs_reclaim calls the MSM shrinker, which calls\ndma_resv_lock. This in turn acquires fs_reclaim.\n\nFix this deadlock by using dma_resv_trylock() instead, dropping the\nsubsequently unused passed wait-wound lock 'ticket'.\n\nPatchwork: https://patchwork.freedesktop.org/patch/723564/\n[rob: fixup compile errors, replace lockdep splat with somethin\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-667"],"references":["https://git.kernel.org/stable/c/3392291fc509d8ad6e4ad90f15b0a193f721cbc9","https://git.kernel.org/stable/c/928788566c79046f71a211fc32c115400be76402","https://git.kernel.org/stable/c/942968260e61d4a5d7552b20814b6277f9c553df"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:45:36.895656543+00:00"},"epss":{"cve":"CVE-2026-64100","score":0.00124,"percentile":0.02083,"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."]}