KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache

Status: premoderation: reported on 2026/08/04 13:01
Reported-by: syzbot+bb423d71dd25405fd560@syzkaller.appspotmail.com
First crash: 18d, last: 4d10h
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache 19 7 5d19h 16d 0/2 premoderation: reported on 2026/08/06 00:17

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in trace_event_raw_event_mm_filemap_op_page_cache+0x3c6/0x3f0 include/trace/events/filemap.h:-1
Read of size 4 at addr ffff888128659010 by task syz.8.2636/10030

CPU: 0 PID: 10030 Comm: syz.8.2636 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x10f/0x150 mm/kasan/report.c:444
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 trace_event_raw_event_mm_filemap_op_page_cache+0x3c6/0x3f0 include/trace/events/filemap.h:-1
 trace_mm_filemap_delete_from_page_cache include/trace/events/filemap.h:47 [inline]
 __delete_from_page_cache+0x418/0x470 mm/filemap.c:238
 __remove_mapping+0x601/0x990 mm/vmscan.c:1216
 shrink_page_list+0x2a24/0x5800 mm/vmscan.c:1829
 shrink_inactive_list mm/vmscan.c:2338 [inline]
 shrink_list mm/vmscan.c:2583 [inline]
 shrink_lruvec+0x1297/0x3a40 mm/vmscan.c:5800
 shrink_node_memcgs mm/vmscan.c:5992 [inline]
 shrink_node+0x11ee/0x2a40 mm/vmscan.c:6022
 shrink_zones mm/vmscan.c:6228 [inline]
 do_try_to_free_pages+0x5a7/0x1580 mm/vmscan.c:6286
 try_to_free_mem_cgroup_pages+0x261/0x610 mm/vmscan.c:6600
 mem_cgroup_force_empty mm/memcontrol.c:3591 [inline]
 mem_cgroup_force_empty_write+0x130/0x170 mm/memcontrol.c:3612
 cgroup_file_write+0x294/0x560 kernel/cgroup/cgroup.c:4011
 kernfs_fop_write_iter+0x2bd/0x400 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2212 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x831/0xfd0 fs/read_write.c:594
 ksys_write+0x14a/0x260 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:656
 x64_sys_call+0x8ef/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4a87a750d9
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:00007f4a864ce028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4a87cfcfa0 RCX: 00007f4a87a750d9
RDX: 0000000000000002 RSI: 00002000000002c0 RDI: 0000000000000003
RBP: 00007f4a87b0c024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4a87cfd038 R14: 00007f4a87cfcfa0 R15: 00007ffeef598808
 </TASK>

Allocated by task 4097:
 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:433 [inline]
 ____kasan_kmalloc mm/kasan/common.c:512 [inline]
 __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:521
 kasan_kmalloc include/linux/kasan.h:227 [inline]
 __kmalloc+0x13d/0x2c0 mm/slub.c:4436
 __kmalloc_node include/linux/slab.h:487 [inline]
 kmalloc_node include/linux/slab.h:642 [inline]
 kvmalloc_node+0x211/0x320 mm/util.c:621
 kvmalloc include/linux/mm.h:862 [inline]
 kvmalloc_array include/linux/mm.h:880 [inline]
 alloc_fdtable+0x10b/0x2e0 fs/file.c:150
 dup_fd+0x896/0xad0 fs/file.c:345
 copy_files+0x76/0xe0 kernel/fork.c:1625
 copy_process+0x10d4/0x3280 kernel/fork.c:2341
 kernel_clone+0x233/0x960 kernel/fork.c:2742
 __do_sys_clone kernel/fork.c:2868 [inline]
 __se_sys_clone kernel/fork.c:2852 [inline]
 __x64_sys_clone+0x198/0x210 kernel/fork.c:2852
 x64_sys_call+0x41f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

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+0x51/0x310 kernel/workqueue.c:1373
 __queue_work+0x8e1/0xc60 kernel/workqueue.c:1539
 queue_work_on+0xde/0x150 kernel/workqueue.c:1566
 queue_work include/linux/workqueue.h:510 [inline]
 schedule_work include/linux/workqueue.h:571 [inline]
 destroy_super_rcu+0xd1/0xe0 fs/super.c:172
 rcu_do_batch+0x4c1/0xbf0 kernel/rcu/tree.c:2523
 rcu_core+0x4a3/0xef0 kernel/rcu/tree.c:2763
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2776
 handle_softirqs+0x250/0x560 kernel/softirq.c:583
 __do_softirq kernel/softirq.c:621 [inline]
 invoke_softirq kernel/softirq.c:443 [inline]
 __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:670
 irq_exit_rcu+0x9/0x10 kernel/softirq.c:682
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:676

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_common kernel/rcu/tree.c:3011 [inline]
 call_rcu+0x10b/0xf60 kernel/rcu/tree.c:3129
 __put_super+0x26b/0x2d0 fs/super.c:299
 put_super fs/super.c:313 [inline]
 deactivate_locked_super+0xd4/0x100 fs/super.c:346
 mount_bdev+0x2ab/0x3c0 fs/super.c:1402
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4713
 legacy_get_tree+0xed/0x190 fs/fs_context.c:611
 vfs_get_tree+0x89/0x260 fs/super.c:1530
 do_new_mount+0x251/0xb40 fs/namespace.c:3037
 path_mount+0x640/0xff0 fs/namespace.c:3367
 do_mount fs/namespace.c:3380 [inline]
 __do_sys_mount fs/namespace.c:3588 [inline]
 __se_sys_mount+0x320/0x390 fs/namespace.c:3565
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3565
 x64_sys_call+0x6bf/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888128659000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
 2048-byte region [ffff888128659000, ffff888128659800)
The buggy address belongs to the page:
page:ffffea0004a19600 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888128659000 pfn:0x128658
head:ffffea0004a19600 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea000435ac08 ffffea0004177608 ffff888100043200
raw: ffff888128659000 0000000000080003 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 288, ts 23879890285, free_ts 0
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
 get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1937 [inline]
 new_slab+0xa0/0x4d0 mm/slub.c:2000
 ___slab_alloc+0x3ac/0x840 mm/slub.c:3033
 __slab_alloc+0x49/0x90 mm/slub.c:3120
 slab_alloc_node mm/slub.c:3211 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 __kmalloc+0x16a/0x2c0 mm/slub.c:4432
 kmalloc include/linux/slab.h:624 [inline]
 kzalloc include/linux/slab.h:750 [inline]
 __register_sysctl_table+0xeb/0x1240 fs/proc/proc_sysctl.c:1326
 register_net_sysctl+0x21d/0x230 net/sysctl_net.c:169
 __devinet_sysctl_register+0x2bd/0x390 net/ipv4/devinet.c:2604
 devinet_sysctl_register+0x169/0x1e0 net/ipv4/devinet.c:2644
 inetdev_init+0x2b2/0x500 net/ipv4/devinet.c:284
 inetdev_event+0x1f4/0x1060 net/ipv4/devinet.c:1544
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2070 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2082 [inline]
 call_netdevice_notifiers+0x119/0x190 net/core/dev.c:2096
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888128658f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888128658f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888128659000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888128659080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888128659100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/18 03:05 android13-5.15-lts 9c43b169ac7e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/18 03:03 android13-5.15-lts 9c43b169ac7e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/15 12:51 android13-5.15-lts 54275df9611d 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/12 13:05 android13-5.15-lts 54275df9611d f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/12 10:20 android13-5.15-lts 54275df9611d f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/10 02:14 android13-5.15-lts 6148a1b6bae4 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/06 08:07 android13-5.15-lts b885b84af7a2 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/05 15:23 android13-5.15-lts b885b84af7a2 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/05 14:52 android13-5.15-lts b885b84af7a2 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
2026/08/04 13:00 android13-5.15-lts b885b84af7a2 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 KASAN: use-after-free Read in trace_event_raw_event_mm_filemap_op_page_cache
* Struck through repros no longer work on HEAD.