KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache

Status: premoderation: reported on 2026/08/06 00:17
Reported-by: syzbot+df0848ecb10a50bba795@syzkaller.appspotmail.com
First crash: 40d, last: 2d07h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache 19 26 1d13h 42d 0/2 premoderation: reported on 2026/08/04 13:01

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in trace_event_raw_event_mm_filemap_op_page_cache+0x38a/0x3b0 include/trace/events/filemap.h:-1
Read of size 4 at addr ffff888113c60010 by task syz.3.288/1722

CPU: 0 PID: 1722 Comm: syz.3.288 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x100/0x140 mm/kasan/report.c:452
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 trace_event_raw_event_mm_filemap_op_page_cache+0x38a/0x3b0 include/trace/events/filemap.h:-1
 trace_mm_filemap_delete_from_page_cache include/trace/events/filemap.h:47 [inline]
 __delete_from_page_cache+0x429/0x470 mm/filemap.c:241
 __remove_mapping+0x581/0x6b0 mm/vmscan.c:985
 shrink_page_list+0x21ee/0x4160 mm/vmscan.c:1498
 evict_pages+0x39c4/0x5080 mm/vmscan.c:4556
 lru_gen_shrink_lruvec mm/vmscan.c:4740 [inline]
 shrink_lruvec+0x123b/0x2d70 mm/vmscan.c:5437
 shrink_node_memcgs mm/vmscan.c:5660 [inline]
 shrink_node+0xee0/0x2690 mm/vmscan.c:5690
 shrink_zones mm/vmscan.c:5896 [inline]
 do_try_to_free_pages+0x602/0x1590 mm/vmscan.c:5954
 try_to_free_mem_cgroup_pages+0x261/0x610 mm/vmscan.c:6272
 mem_cgroup_force_empty mm/memcontrol.c:3520 [inline]
 mem_cgroup_force_empty_write+0x130/0x170 mm/memcontrol.c:3541
 cgroup_file_write+0x294/0x560 kernel/cgroup/cgroup.c:3902
 kernfs_fop_write_iter+0x2bd/0x400 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2072 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x770/0xd70 fs/read_write.c:605
 ksys_write+0x14a/0x260 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:667
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7ff3e651c159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff3e4f75028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff3e67a3fa0 RCX: 00007ff3e651c159
RDX: 0000000000000001 RSI: 00002000000002c0 RDI: 0000000000000004
RBP: 00007ff3e65b303b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff3e67a4038 R14: 00007ff3e67a3fa0 R15: 00007ffca58986e8

Allocated by task 1622:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 ____kasan_kmalloc mm/kasan/common.c:509 [inline]
 __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:518
 kasan_kmalloc include/linux/kasan.h:254 [inline]
 kmem_cache_alloc_trace+0x179/0x2e0 mm/slub.c:2979
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:667 [inline]
 alloc_super+0x5a/0x7d0 fs/super.c:203
 sget+0x1e2/0x4c0 fs/super.c:627
 mount_bdev+0xec/0x380 fs/super.c:1426
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4598
 legacy_get_tree+0xed/0x190 fs/fs_context.c:593
 vfs_get_tree+0x89/0x260 fs/super.c:1583
 do_new_mount+0x25a/0xa30 fs/namespace.c:3006
 path_mount+0x581/0xca0 fs/namespace.c:3336
 do_mount fs/namespace.c:3349 [inline]
 __do_sys_mount fs/namespace.c:3557 [inline]
 __se_sys_mount+0x320/0x390 fs/namespace.c:3534
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3534
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 496:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1600 [inline]
 slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626
 slab_free mm/slub.c:3208 [inline]
 kfree+0xc0/0x270 mm/slub.c:4196
 destroy_super_work+0x40/0x50 fs/super.c:165
 process_one_work+0x6fd/0xbc0 kernel/workqueue.c:2301
 worker_thread+0xa8e/0x13c0 kernel/workqueue.c:2447
 kthread+0x324/0x3b0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 insert_work+0x51/0x320 kernel/workqueue.c:1352
 __queue_work+0x91f/0xca0 kernel/workqueue.c:1518
 queue_work_on+0xe6/0x140 kernel/workqueue.c:1545
 queue_work include/linux/workqueue.h:515 [inline]
 schedule_work include/linux/workqueue.h:576 [inline]
 destroy_super_rcu+0xd1/0xe0 fs/super.c:172
 rcu_do_batch+0x488/0xaf0 kernel/rcu/tree.c:2494
 rcu_core+0x50a/0xca0 kernel/rcu/tree.c:2735
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2748
 __do_softirq+0x255/0x563 kernel/softirq.c:309

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 __call_rcu kernel/rcu/tree.c:2980 [inline]
 call_rcu+0x11a/0x1090 kernel/rcu/tree.c:3054
 __put_super+0x254/0x2b0 fs/super.c:299
 put_super fs/super.c:313 [inline]
 deactivate_locked_super+0xd4/0x100 fs/super.c:346
 mount_bdev+0x288/0x380 fs/super.c:1455
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4598
 legacy_get_tree+0xed/0x190 fs/fs_context.c:593
 vfs_get_tree+0x89/0x260 fs/super.c:1583
 do_new_mount+0x25a/0xa30 fs/namespace.c:3006
 path_mount+0x581/0xca0 fs/namespace.c:3336
 do_mount fs/namespace.c:3349 [inline]
 __do_sys_mount fs/namespace.c:3557 [inline]
 __se_sys_mount+0x320/0x390 fs/namespace.c:3534
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3534
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff888113c60000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
 2048-byte region [ffff888113c60000, ffff888113c60800)
The buggy address belongs to the page:
page:ffffea00044f1800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x113c60
head:ffffea00044f1800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100042d80
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 423, ts 28404019209, free_ts 28397287936
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x176/0x190 mm/page_alloc.c:2462
 get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1813 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1874
 new_slab_objects mm/slub.c:2632 [inline]
 ___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796
 __slab_alloc+0x63/0xa0 mm/slub.c:2836
 slab_alloc_node mm/slub.c:2918 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 __kmalloc_track_caller+0x1e4/0x310 mm/slub.c:4541
 __kmalloc_reserve net/core/skbuff.c:144 [inline]
 __alloc_skb+0xdc/0x520 net/core/skbuff.c:212
 alloc_skb include/linux/skbuff.h:1126 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 audit_buffer_alloc kernel/audit.c:1806 [inline]
 audit_log_start+0x41b/0x840 kernel/audit.c:1924
 common_lsm_audit+0xd4/0x1850 security/lsm_audit.c:457
 slow_avc_audit+0x1c4/0x240 security/selinux/avc.c:798
 avc_xperms_audit security/selinux/avc.c:433 [inline]
 avc_has_extended_perms+0x770/0xc90 security/selinux/avc.c:1118
 ioctl_has_perm+0x3a6/0x4f0 security/selinux/hooks.c:3676
 selinux_file_ioctl+0x3ad/0x4c0 security/selinux/hooks.c:-1
 security_file_ioctl+0x74/0xa0 security/security.c:1469
 __do_sys_ioctl fs/ioctl.c:747 [inline]
 __se_sys_ioctl+0x53/0x1a0 fs/ioctl.c:739
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 __free_pages_ok+0x80b/0x830 mm/page_alloc.c:1629
 free_the_page mm/page_alloc.c:5445 [inline]
 __free_pages+0xd8/0x390 mm/page_alloc.c:5454
 __free_slab+0xcf/0x190 mm/slub.c:1899
 free_slab mm/slub.c:1914 [inline]
 discard_slab mm/slub.c:1920 [inline]
 unfreeze_partials+0x150/0x180 mm/slub.c:2415
 put_cpu_partial+0xc1/0x180 mm/slub.c:2451
 __slab_free+0x2c9/0x3a0 mm/slub.c:3100
 do_slab_free mm/slub.c:3196 [inline]
 ___cache_free+0x10e/0x130 mm/slub.c:3215
 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:440
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580
 slab_alloc_node mm/slub.c:2952 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x15a/0x2d0 mm/slub.c:2965
 vm_area_dup+0x26/0x250 kernel/fork.c:366
 dup_mmap kernel/fork.c:550 [inline]
 dup_mm kernel/fork.c:1435 [inline]
 copy_mm+0x857/0x13d0 kernel/fork.c:1491
 copy_process+0x1386/0x3320 kernel/fork.c:2268

Memory state around the buggy address:
 ffff888113c5ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888113c5ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888113c60000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888113c60080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888113c60100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (23):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/13 05:50 android13-5.10-lts 452567d1985b 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/12 20:16 android13-5.10-lts 452567d1985b 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/12 19:53 android13-5.10-lts 452567d1985b 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/12 02:28 android13-5.10-lts 452567d1985b 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/11 05:14 android13-5.10-lts 452567d1985b 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/10 16:14 android13-5.10-lts 452567d1985b 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/08 16:15 android13-5.10-lts 452567d1985b 243b72f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/08 16:14 android13-5.10-lts 452567d1985b 243b72f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/08 16:13 android13-5.10-lts 452567d1985b 243b72f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/06 00:11 android13-5.10-lts 452567d1985b 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/05 22:19 android13-5.10-lts 452567d1985b 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/30 13:07 android13-5.10-lts 174d3ccb72b8 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/30 00:33 android13-5.10-lts 174d3ccb72b8 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/28 11:44 android13-5.10-lts 174d3ccb72b8 e2fa417d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/27 22:59 android13-5.10-lts 174d3ccb72b8 69a01293 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/16 17:41 android13-5.10-lts e334a66065d3 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/15 08:59 android13-5.10-lts e334a66065d3 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/15 02:50 android13-5.10-lts e334a66065d3 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/15 02:43 android13-5.10-lts e334a66065d3 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/12 13:13 android13-5.10-lts 8e2d2cc88387 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/12 04:39 android13-5.10-lts dce28bf8c73c f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/06 00:16 android13-5.10-lts 0f73d4924a74 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/09/02 05:20 android13-5.10-lts 4185c27befd4 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Read in trace_event_raw_event_mm_filemap_op_page_cache
* Struck through repros no longer work on HEAD.