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kernel BUG in folio_end_read (3)

Status: fixed on 2026/05/22 08:51
Subsystems: f2fs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+337ec6af661bd91fa43a@syzkaller.appspotmail.com
Fix commit: 570e2ccc7cb3 f2fs: avoid reading already updated pages during GC
First crash: 63d, last: 63d
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
700faf44-6f7f-4918-bf85-029b478e66df assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ kernel BUG in folio_end_read (3) 2026/05/20 10:18 2026/05/20 10:18 2026/05/20 11:03 62fb93a255739705450473a63391e4b93a0c5545
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [f2fs?] kernel BUG in folio_end_read (3) 1 (2) 2026/04/29 07:40
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in folio_end_read f2fs -1 81 376d 489d 0/29 auto-obsoleted due to no activity on 2025/08/10 18:25
upstream kernel BUG in folio_end_read (2) iomap -1 C done 138 203d 267d 0/29 auto-obsoleted due to no activity on 2026/01/30 06:26

Sample crash report:
page: refcount:2 mapcount:0 mapping:ffff888046f3e788 index:0x1507 pfn:0x32d0e
memcg:ffff88801c6c8d40
aops:f2fs_meta_aops ino:2
flags: 0x4fff400000000a9(locked|waiters|uptodate|lru|node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff400000000a9 ffffea0000d1b988 ffff888030450a80 ffff888046f3e788
raw: 0000000000001507 0000000000000000 00000002ffffffff ffff88801c6c8d40
page dumped because: VM_BUG_ON_FOLIO(success && folio_test_uptodate(folio))
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x40c40(GFP_NOFS|__GFP_COMP), pid 5318, tgid 5316 (syz.0.0), ts 76502021566, free_ts 42035680990
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2490
 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline]
 alloc_pages_noprof+0xa8/0x1a0 mm/mempolicy.c:2581
 folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2591
 filemap_alloc_folio_noprof+0x111/0x470 mm/filemap.c:1013
 __filemap_get_folio_mpol+0x3fc/0xb00 mm/filemap.c:2011
 __filemap_get_folio include/linux/pagemap.h:763 [inline]
 f2fs_filemap_get_folio fs/f2fs/f2fs.h:3065 [inline]
 ra_data_block+0x544/0xd00 fs/f2fs/gc.c:1277
 gc_data_segment fs/f2fs/gc.c:1648 [inline]
 do_garbage_collect+0x358d/0x7080 fs/f2fs/gc.c:1874
 f2fs_gc+0xca2/0x2570 fs/f2fs/gc.c:1981
 f2fs_balance_fs+0x657/0x840 fs/f2fs/segment.c:467
 f2fs_map_blocks+0x2958/0x4340 fs/f2fs/data.c:1826
 f2fs_iomap_begin+0x3bd/0x8f0 fs/f2fs/data.c:4527
 iomap_iter+0x600/0x1020 fs/iomap/iter.c:110
 __iomap_dio_rw+0x1360/0x1ea0 fs/iomap/direct-io.c:795
page last free pid 15 tgid 15 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x870 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1063
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
------------[ cut here ]------------
kernel BUG at mm/filemap.c:1536!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 42 Comm: kworker/u4:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: loop0 loop_workfn
RIP: 0010:folio_end_read+0x22e/0x230 mm/filemap.c:1536
Code: 6f c3 ff 48 89 df 48 c7 c6 e0 c4 d7 8b e8 ba ba 25 ff 90 0f 0b e8 02 6f c3 ff 48 89 df 48 c7 c6 40 bb d7 8b e8 a3 ba 25 ff 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa
RSP: 0018:ffffc90000447478 EFLAGS: 00010246
RAX: b965f80585da9300 RBX: ffffea0000cb4380 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffffffff8deff28a RDI: 00000000ffffffff
RBP: 0000000000000001 R08: ffffffff9011feb7 R09: 1ffffffff2023fd6
R10: dffffc0000000000 R11: fffffbfff2023fd7 R12: 1ffffd4000196871
R13: 1ffffd4000196870 R14: ffffea0000cb4388 R15: 0000000000000008
FS:  0000000000000000(0000) GS:ffff88808ca49000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8b147ff000 CR3: 0000000038c3d000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 f2fs_finish_read_bio+0x4fc/0x940 fs/f2fs/data.c:182
 blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
 lo_rw_aio_complete drivers/block/loop.c:337 [inline]
 lo_rw_aio+0xcde/0xf00 drivers/block/loop.c:409
 do_req_filebacked drivers/block/loop.c:435 [inline]
 loop_handle_cmd drivers/block/loop.c:1925 [inline]
 loop_process_work+0x958/0x11a0 drivers/block/loop.c:1960
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:folio_end_read+0x22e/0x230 mm/filemap.c:1536
Code: 6f c3 ff 48 89 df 48 c7 c6 e0 c4 d7 8b e8 ba ba 25 ff 90 0f 0b e8 02 6f c3 ff 48 89 df 48 c7 c6 40 bb d7 8b e8 a3 ba 25 ff 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa
RSP: 0018:ffffc90000447478 EFLAGS: 00010246
RAX: b965f80585da9300 RBX: ffffea0000cb4380 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffffffff8deff28a RDI: 00000000ffffffff
RBP: 0000000000000001 R08: ffffffff9011feb7 R09: 1ffffffff2023fd6
R10: dffffc0000000000 R11: fffffbfff2023fd7 R12: 1ffffd4000196871
R13: 1ffffd4000196870 R14: ffffea0000cb4388 R15: 0000000000000008
FS:  0000000000000000(0000) GS:ffff88808ca49000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8b147ff000 CR3: 0000000038c3d000 CR4: 0000000000352ef0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/10 03:06 upstream a55f7f5f29b3 38c8e246 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in folio_end_read
* Struck through repros no longer work on HEAD.