================================================================== 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 ffff8881293b0010 by task syz.1.2904/10267 CPU: 1 PID: 10267 Comm: syz.1.2904 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: __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_resize_max+0x309/0x3e0 mm/memcontrol.c:3478 mem_cgroup_write+0x1ed/0x230 mm/memcontrol.c:-1 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: 0033:0x7f644a14f159 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:00007f6448b87028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f644a3d7090 RCX: 00007f644a14f159 RDX: 0000000000000001 RSI: 0000200000000080 RDI: 000000000000000b RBP: 00007f644a1e6024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f644a3d7128 R14: 00007f644a3d7090 R15: 00007fffb7a0a6f8 Allocated by task 101: 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] seq_buf_alloc fs/seq_file.c:38 [inline] seq_read_iter+0x1f1/0xce0 fs/seq_file.c:210 kernfs_fop_read_iter+0x146/0x460 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2206 [inline] new_sync_read fs/read_write.c:404 [inline] vfs_read+0x6c0/0xc20 fs/read_write.c:485 ksys_read+0x14a/0x260 fs/read_write.c:623 __do_sys_read fs/read_write.c:633 [inline] __se_sys_read fs/read_write.c:631 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:631 x64_sys_call+0x96d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1 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 Freed by task 101: 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:365 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373 kasan_slab_free include/linux/kasan.h:193 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754 slab_free mm/slub.c:3526 [inline] kfree+0xc4/0x270 mm/slub.c:4588 kvfree+0x35/0x40 mm/util.c:661 seq_release+0x57/0x70 fs/seq_file.c:355 kernfs_fop_release+0x195/0x240 fs/kernfs/file.c:761 __fput+0x22b/0x900 fs/file_table.c:311 ____fput+0x15/0x20 fs/file_table.c:339 task_work_run+0x127/0x190 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff8881293b0000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 16 bytes inside of 4096-byte region [ffff8881293b0000, ffff8881293b1000) The buggy address belongs to the page: page:ffffea0004a4ec00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1293b0 head:ffffea0004a4ec00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 0000000000000000 dead000000000122 ffff888100043380 raw: 0000000000000000 0000000000040004 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 101, ts 661559177728, free_ts 661497065218 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] kmem_cache_alloc_trace+0x146/0x270 mm/slub.c:3272 kmalloc include/linux/slab.h:619 [inline] kzalloc include/linux/slab.h:750 [inline] kernfs_iop_get_link+0x66/0x600 fs/kernfs/symlink.c:136 vfs_readlink+0x16f/0x3e0 fs/namei.c:5089 do_readlinkat+0x251/0x490 fs/stat.c:454 __do_sys_readlink fs/stat.c:475 [inline] __se_sys_readlink fs/stat.c:472 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:472 x64_sys_call+0x93c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:90 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 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1474 [inline] free_pcp_prepare mm/page_alloc.c:1546 [inline] free_unref_page_prepare+0x5fa/0x600 mm/page_alloc.c:3536 free_unref_page+0xae/0x540 mm/page_alloc.c:3618 free_the_page mm/page_alloc.c:805 [inline] __free_pages+0x6c/0x100 mm/page_alloc.c:5900 __free_slab+0xe5/0x1e0 mm/slub.c:2025 free_slab mm/slub.c:2040 [inline] discard_slab mm/slub.c:2046 [inline] __unfreeze_partials+0x15a/0x190 mm/slub.c:2532 put_cpu_partial+0xc6/0x120 mm/slub.c:2612 __slab_free+0x1d4/0x290 mm/slub.c:3395 do_slab_free mm/slub.c:3514 [inline] ___cache_free+0x104/0x120 mm/slub.c:3535 qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:443 kasan_slab_alloc include/linux/kasan.h:217 [inline] slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550 slab_alloc_node mm/slub.c:3245 [inline] slab_alloc mm/slub.c:3255 [inline] kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260 kmem_cache_zalloc include/linux/slab.h:740 [inline] taskstats_tgid_alloc kernel/taskstats.c:561 [inline] taskstats_exit+0x1eb/0xc50 kernel/taskstats.c:600 do_exit+0x614/0x29a0 kernel/exit.c:866 Memory state around the buggy address: ffff8881293aff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881293aff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881293b0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881293b0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881293b0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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