{"id":"CVE-2026-64100","summary":"drm/msm: Fix shrinker deadlock","details":"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   -\u003e #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   -\u003e #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   -\u003e #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 --\u003e reservation_ww_class_mutex --\u003e 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---","modified":"2026-07-21T03:46:52.447609031Z","published":"2026-07-19T15:40:05.530Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64100.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3392291fc509d8ad6e4ad90f15b0a193f721cbc9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/928788566c79046f71a211fc32c115400be76402"},{"type":"WEB","url":"https://git.kernel.org/stable/c/942968260e61d4a5d7552b20814b6277f9c553df"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64100.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64100"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fe4952b5f27cca5d143d3de249562d4cc984c1d6"},{"fixed":"942968260e61d4a5d7552b20814b6277f9c553df"},{"fixed":"928788566c79046f71a211fc32c115400be76402"},{"fixed":"3392291fc509d8ad6e4ad90f15b0a193f721cbc9"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-64100.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.18.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-64100.json"}}],"schema_version":"1.7.5"}