* [syzbot] [f2fs?] kernel BUG in f2fs_write_end_io (2)
@ 2026-05-14 20:19 ` syzbot
0 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2026-05-14 20:19 UTC (permalink / raw)
To: chao, jaegeuk, linux-f2fs-devel, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: aa54b1d27fe0 rxrpc: Also unshare DATA/RESPONSE packets whe..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14adabce580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f2e8ebfec4636d32
dashboard link: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1643c3ce580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12adabce580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/418e3ed628cf/disk-aa54b1d2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a35b53d0ab2f/vmlinux-aa54b1d2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/03c3fa0081b4/bzImage-aa54b1d2.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/13e397c7f935/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=158fad06580000)
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/2f91edde40dc/mount_8.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4af46ee83100e99bce09@syzkaller.appspotmail.com
------------[ cut here ]------------
kernel BUG at fs/f2fs/data.c:388!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 31 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:f2fs_write_end_io+0x16df/0x1740 fs/f2fs/data.c:388
Code: 20 3c 9b 8b e8 12 0a f7 fc 90 0f 0b e8 0a cc 93 fd 48 8b 3c 24 48 c7 c6 20 3c 9b 8b e8 fa 09 f7 fc 90 0f 0b e8 f2 cb 93 fd 90 <0f> 0b e8 ea cb 93 fd 48 8b 3c 24 48 c7 c6 20 3c 9b 8b e8 da 09 f7
RSP: 0018:ffffc90000a5fb18 EFLAGS: 00010246
RAX: ffffffff8430aade RBX: ffffea0000d91c40 RCX: ffff88801d6b0000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100
R10: dffffc0000000000 R11: fffffbfff1f11dff R12: 0000000036471000
R13: ffffea0000d91c80 R14: 000000000000000b R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126276000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007eff6352cff8 CR3: 000000002caa2000 CR4: 00000000003526f0
Call Trace:
<TASK>
blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
blk_complete_reqs block/blk-mq.c:1253 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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:f2fs_write_end_io+0x16df/0x1740 fs/f2fs/data.c:388
Code: 20 3c 9b 8b e8 12 0a f7 fc 90 0f 0b e8 0a cc 93 fd 48 8b 3c 24 48 c7 c6 20 3c 9b 8b e8 fa 09 f7 fc 90 0f 0b e8 f2 cb 93 fd 90 <0f> 0b e8 ea cb 93 fd 48 8b 3c 24 48 c7 c6 20 3c 9b 8b e8 da 09 f7
RSP: 0018:ffffc90000a5fb18 EFLAGS: 00010246
RAX: ffffffff8430aade RBX: ffffea0000d91c40 RCX: ffff88801d6b0000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100
R10: dffffc0000000000 R11: fffffbfff1f11dff R12: 0000000036471000
R13: ffffea0000d91c80 R14: 000000000000000b R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126276000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007eff6352cff8 CR3: 000000002caa2000 CR4: 00000000003526f0
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 8+ messages in thread* [f2fs-dev] [syzbot] [f2fs?] kernel BUG in f2fs_write_end_io (2) @ 2026-05-14 20:19 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-05-14 20:19 UTC (permalink / raw) To: chao, jaegeuk, linux-f2fs-devel, linux-kernel, syzkaller-bugs Hello, syzbot found the following issue on: HEAD commit: aa54b1d27fe0 rxrpc: Also unshare DATA/RESPONSE packets whe.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14adabce580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f2e8ebfec4636d32 dashboard link: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1643c3ce580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12adabce580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/418e3ed628cf/disk-aa54b1d2.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/a35b53d0ab2f/vmlinux-aa54b1d2.xz kernel image: https://storage.googleapis.com/syzbot-assets/03c3fa0081b4/bzImage-aa54b1d2.xz mounted in repro #1: https://storage.googleapis.com/syzbot-assets/13e397c7f935/mount_0.gz fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=158fad06580000) mounted in repro #2: https://storage.googleapis.com/syzbot-assets/2f91edde40dc/mount_8.gz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4af46ee83100e99bce09@syzkaller.appspotmail.com ------------[ cut here ]------------ kernel BUG at fs/f2fs/data.c:388! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 31 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:f2fs_write_end_io+0x16df/0x1740 fs/f2fs/data.c:388 Code: 20 3c 9b 8b e8 12 0a f7 fc 90 0f 0b e8 0a cc 93 fd 48 8b 3c 24 48 c7 c6 20 3c 9b 8b e8 fa 09 f7 fc 90 0f 0b e8 f2 cb 93 fd 90 <0f> 0b e8 ea cb 93 fd 48 8b 3c 24 48 c7 c6 20 3c 9b 8b e8 da 09 f7 RSP: 0018:ffffc90000a5fb18 EFLAGS: 00010246 RAX: ffffffff8430aade RBX: ffffea0000d91c40 RCX: ffff88801d6b0000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: fffffbfff1f11dff R12: 0000000036471000 R13: ffffea0000d91c80 R14: 000000000000000b R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126276000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007eff6352cff8 CR3: 000000002caa2000 CR4: 00000000003526f0 Call Trace: <TASK> blk_update_request+0x57e/0xe60 block/blk-mq.c:1016 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178 blk_complete_reqs block/blk-mq.c:1253 [inline] blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622 run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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:f2fs_write_end_io+0x16df/0x1740 fs/f2fs/data.c:388 Code: 20 3c 9b 8b e8 12 0a f7 fc 90 0f 0b e8 0a cc 93 fd 48 8b 3c 24 48 c7 c6 20 3c 9b 8b e8 fa 09 f7 fc 90 0f 0b e8 f2 cb 93 fd 90 <0f> 0b e8 ea cb 93 fd 48 8b 3c 24 48 c7 c6 20 3c 9b 8b e8 da 09 f7 RSP: 0018:ffffc90000a5fb18 EFLAGS: 00010246 RAX: ffffffff8430aade RBX: ffffea0000d91c40 RCX: ffff88801d6b0000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: fffffbfff1f11dff R12: 0000000036471000 R13: ffffea0000d91c80 R14: 000000000000000b R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126276000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007eff6352cff8 CR3: 000000002caa2000 CR4: 00000000003526f0 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ^ permalink raw reply [flat|nested] 8+ messages in thread
* Forwarded: [PATCH] f2fs: DEBUG: trace node folio lifecycle to diagnose write_end_io BUG 2026-05-14 20:19 ` [f2fs-dev] " syzbot (?) @ 2026-05-14 23:35 ` syzbot -1 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-05-14 23:35 UTC (permalink / raw) To: linux-kernel, syzkaller-bugs For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] f2fs: DEBUG: trace node folio lifecycle to diagnose write_end_io BUG Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master Not for upstream. Instrumentation to identify which path leaves a node folio with folio->index != nid_of_node(folio) at writeback time, triggering the BUG in f2fs_write_end_io() reported by syzbot. Adds pr_info trace points at: - f2fs_new_node_folio() - in-memory node folio construction - __get_node_folio() - node folio lookup (cache or read) - __get_node_folio() - synchronous footer sanity failure - f2fs_finish_read_bio() - async read completion footer check - f2fs_write_end_io() - write completion footer check BUG_ON in f2fs_write_end_io() is intentionally retained so the kernel halts at the failing folio and the preceding pr_info output appears in the syzbot console log. Link: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09 Not-Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com> --- fs/f2fs/data.c | 19 ++++++++++++++----- fs/f2fs/node.c | 5 +++++ 2 files changed, 19 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 8d4f1e75dee3..dc01a4fe089a 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -174,10 +174,17 @@ static void f2fs_finish_read_bio(struct bio *bio, bool in_task) dec_page_count(F2FS_F_SB(folio), __read_io_type(folio)); if (bio->bi_status == BLK_STS_OK && - F2FS_F_SB(folio)->node_inode && is_node_folio(folio) && - f2fs_sanity_check_node_footer(F2FS_F_SB(folio), - folio, folio->index, NODE_TYPE_REGULAR, true)) - bio->bi_status = BLK_STS_IOERR; + F2FS_F_SB(folio)->node_inode && is_node_folio(folio)) { + int rc = f2fs_sanity_check_node_footer(F2FS_F_SB(folio), + folio, folio->index, NODE_TYPE_REGULAR, true); + pr_info("f2fs-dbg: READ end_io: index=%lu footer_nid=%u ino=%u rc=%d\n", + folio->index, + nid_of_node(folio), + ino_of_node(folio), + rc); + if (rc) + bio->bi_status = BLK_STS_IOERR; + } if (finished) folio_end_read(folio, bio->bi_status == BLK_STS_OK); @@ -383,8 +390,10 @@ static void f2fs_write_end_io(struct bio *bio) } if (is_node_folio(folio)) { - f2fs_sanity_check_node_footer(sbi, folio, + int rc = f2fs_sanity_check_node_footer(sbi, folio, folio->index, NODE_TYPE_REGULAR, true); + pr_info("f2fs-dbg: WRITE end_io: index=%lu footer_nid=%u ino=%u rc=%d\n", + folio->index,nid_of_node(folio),ino_of_node(folio),rc); f2fs_bug_on(sbi, folio->index != nid_of_node(folio)); } if (f2fs_in_warm_node_list(folio)) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 4e5bd9e4cfc3..12a9774ac1df 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1423,6 +1423,8 @@ struct folio *f2fs_new_node_folio(struct dnode_of_data *dn, unsigned int ofs) f2fs_folio_wait_writeback(folio, NODE, true, true); fill_node_footer(folio, dn->nid, dn->inode->i_ino, ofs, true); set_cold_node(folio, S_ISDIR(dn->inode->i_mode)); + pr_info("f2fs-dbg: NEW node_folio: nid=%u ino=%lu ofs=%u\n", + dn->nid, dn->inode->i_ino, ofs); if (!folio_test_uptodate(folio)) folio_mark_uptodate(folio); if (folio_mark_dirty(folio)) @@ -1565,6 +1567,7 @@ static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid, struct folio *folio; int err; + pr_info("f2fs-dbg: GET node_folio: nid=%lu ntype=%d\n", nid, ntype); if (!nid) return ERR_PTR(-ENOENT); if (f2fs_check_nid_range(sbi, nid)) @@ -1603,6 +1606,8 @@ static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid, err = f2fs_sanity_check_node_footer(sbi, folio, nid, ntype, false); if (!err) return folio; + pr_info("f2fs-dbg: SYNC sanity fail: nid=%lu footer_nid=%u ino=%u err=%d\n", + nid,nid_of_node(folio),ino_of_node(folio),err); out_err: folio_clear_uptodate(folio); out_put_err: -- 2.43.0 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Forwarded: [PATCH] f2fs: DEBUG: full lifecycle trace for node folio write-end-io BUG 2026-05-14 20:19 ` [f2fs-dev] " syzbot (?) (?) @ 2026-05-15 1:00 ` syzbot -1 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-05-15 1:00 UTC (permalink / raw) To: linux-kernel, syzkaller-bugs For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] f2fs: DEBUG: full lifecycle trace for node folio write-end-io BUG Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master Not for upstream. Instrumentation to identify how a node folio with mismatched folio->index and nid_of_node(folio) reaches f2fs_write_end_io and triggers the BUG_ON reported by syzbot. Previous test run confirmed the read-side sanity check fires (rc=-EFSCORRUPTED) yet the same folio still reaches writeback. This round adds traces at every cache lifecycle event so the leak path can be pinned down: - f2fs_finish_read_bio - async read footer check, page state - f2fs_write_end_io - write footer check, page state - f2fs_new_node_folio - entry, after grab, after fill_footer, after mark_dirty - read_node_folio - entry, with current page state - __get_node_folio - entry and after grab, page state - __get_node_folio - sync sanity failure on page_hit Each trace logs folio->index, footer nid/ino, and the relevant page flags (uptodate, dirty, writeback, refcount) so the journey of a single NID can be reconstructed across read failure, cache reuse, and writeback submission. BUG_ON in f2fs_write_end_io() is intentionally retained so the kernel halts at the failing folio and the preceding trace output appears in the syzbot console log. Link: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09 Not-Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com> --- fs/f2fs/data.c | 16 +++++++++++----- fs/f2fs/node.c | 19 ++++++++++++++++++- 2 files changed, 29 insertions(+), 6 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 8d4f1e75dee3..571ba13916ef 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -174,10 +174,14 @@ static void f2fs_finish_read_bio(struct bio *bio, bool in_task) dec_page_count(F2FS_F_SB(folio), __read_io_type(folio)); if (bio->bi_status == BLK_STS_OK && - F2FS_F_SB(folio)->node_inode && is_node_folio(folio) && - f2fs_sanity_check_node_footer(F2FS_F_SB(folio), - folio, folio->index, NODE_TYPE_REGULAR, true)) - bio->bi_status = BLK_STS_IOERR; + F2FS_F_SB(folio)->node_inode && is_node_folio(folio)) { + int rc = f2fs_sanity_check_node_footer(F2FS_F_SB(folio), + folio, folio->index, NODE_TYPE_REGULAR, true); + pr_info("f2fs-dbg: READ end_io: index=%lu footer_nid=%u ino=%u uptodate=%d dirty=%d rc=%d\n", + folio->index,nid_of_node(folio),ino_of_node(folio),folio_test_uptodate(folio),folio_test_dirty(folio),rc); + if (rc) + bio->bi_status = BLK_STS_IOERR; + } if (finished) folio_end_read(folio, bio->bi_status == BLK_STS_OK); @@ -383,8 +387,10 @@ static void f2fs_write_end_io(struct bio *bio) } if (is_node_folio(folio)) { - f2fs_sanity_check_node_footer(sbi, folio, + int rc = f2fs_sanity_check_node_footer(sbi, folio, folio->index, NODE_TYPE_REGULAR, true); + pr_info("f2fs-dbg: WRITE end_io: index=%lu footer_nid=%u ino=%u uptodate=%d dirty=%d rc=%d\n", + folio->index,nid_of_node(folio),ino_of_node(folio),folio_test_uptodate(folio),folio_test_dirty(folio),rc); f2fs_bug_on(sbi, folio->index != nid_of_node(folio)); } if (f2fs_in_warm_node_list(folio)) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 4e5bd9e4cfc3..d38b32fe7ee9 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1384,6 +1384,8 @@ struct folio *f2fs_new_node_folio(struct dnode_of_data *dn, unsigned int ofs) struct folio *folio; int err; + pr_info("f2fs-dbg: NEW entry: nid=%u ino=%lu ofs=%u\n", + dn->nid, dn->inode->i_ino, ofs); if (unlikely(is_inode_flag_set(dn->inode, FI_NO_ALLOC))) return ERR_PTR(-EPERM); @@ -1391,6 +1393,8 @@ struct folio *f2fs_new_node_folio(struct dnode_of_data *dn, unsigned int ofs) if (IS_ERR(folio)) return folio; + pr_info("f2fs-dbg: NEW grabbed: nid=%u uptodate=%d dirty=%d writeback=%d refcount=%d\n", + dn->nid,folio_test_uptodate(folio),folio_test_dirty(folio),folio_test_writeback(folio),folio_ref_count(folio)); if (unlikely((err = inc_valid_node_count(sbi, dn->inode, !ofs)))) goto fail; @@ -1423,10 +1427,14 @@ struct folio *f2fs_new_node_folio(struct dnode_of_data *dn, unsigned int ofs) f2fs_folio_wait_writeback(folio, NODE, true, true); fill_node_footer(folio, dn->nid, dn->inode->i_ino, ofs, true); set_cold_node(folio, S_ISDIR(dn->inode->i_mode)); + pr_info("f2fs-dbg: NEW after fill_footer: nid=%u footer_nid=%u footer_ino=%u\n", + dn->nid, nid_of_node(folio), ino_of_node(folio)); if (!folio_test_uptodate(folio)) folio_mark_uptodate(folio); - if (folio_mark_dirty(folio)) + if (folio_mark_dirty(folio)) { + pr_info("f2fs-dbg: NEW marked dirty: nid=%u\n", dn->nid); dn->node_changed = true; + } if (f2fs_has_xattr_block(ofs)) f2fs_i_xnid_write(dn->inode, dn->nid); @@ -1459,6 +1467,10 @@ static int read_node_folio(struct folio *folio, blk_opf_t op_flags) }; int err; + pr_info("f2fs-dbg: read_node_folio entry: index=%lu uptodate=%d dirty=%d\n", + folio->index, + folio_test_uptodate(folio), + folio_test_dirty(folio)); if (folio_test_uptodate(folio)) { if (!f2fs_inode_chksum_verify(sbi, folio)) { folio_clear_uptodate(folio); @@ -1565,6 +1577,7 @@ static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid, struct folio *folio; int err; + pr_info("f2fs-dbg: GET node_folio: nid=%lu ntype=%d\n", nid, ntype); if (!nid) return ERR_PTR(-ENOENT); if (f2fs_check_nid_range(sbi, nid)) @@ -1574,6 +1587,8 @@ static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid, if (IS_ERR(folio)) return folio; + pr_info("f2fs-dbg: GET grabbed: nid=%lu uptodate=%d dirty=%d writeback=%d refcount=%d\n", + nid,folio_test_uptodate(folio),folio_test_dirty(folio),folio_test_writeback(folio),folio_ref_count(folio)); err = read_node_folio(folio, 0); if (err < 0) goto out_put_err; @@ -1603,6 +1618,8 @@ static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid, err = f2fs_sanity_check_node_footer(sbi, folio, nid, ntype, false); if (!err) return folio; + pr_info("f2fs-dbg: SYNC sanity fail: nid=%lu footer_nid=%u ino=%u err=%d\n", + nid,nid_of_node(folio),ino_of_node(folio),err); out_err: folio_clear_uptodate(folio); out_put_err: -- 2.43.0 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Forwarded: [PATCH] f2fs: don't BUG on node footer mismatch in f2fs_write_end_io 2026-05-14 20:19 ` [f2fs-dev] " syzbot ` (2 preceding siblings ...) (?) @ 2026-05-15 1:55 ` syzbot -1 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-05-15 1:55 UTC (permalink / raw) To: linux-kernel, syzkaller-bugs For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] f2fs: don't BUG on node footer mismatch in f2fs_write_end_io Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master Syzbot reports a recurrence of the kernel BUG in f2fs_write_end_io: kernel BUG at fs/f2fs/data.c:388! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 PREEMPT_{RT,(full)} RIP: 0010:f2fs_write_end_io+0x16df/0x1740 Call Trace: blk_update_request+0x57e/0xe60 blk_mq_end_request+0x3e/0x70 blk_done_softirq+0x10a/0x160 handle_softirqs+0x1de/0x6d0 run_ksoftirqd+0x52/0x180 Commit 50ac3ecd8e05 ("f2fs: fix to do sanity check on node footer in {read,write}_end_io") added f2fs_sanity_check_node_footer() to both end_io paths to catch corrupted node footers reachable from fuzzed on-disk images. In f2fs_write_end_io(), however, the existing f2fs_bug_on(sbi, folio->index != nid_of_node(folio)); was left in place immediately after the new helper call. The helper detects the mismatch, sets SBI_NEED_FSCK and emits a ratelimited warning, but its return value is discarded and the following f2fs_bug_on() panics on the exact same condition. Tracing the reproducer confirms the failure path. A node folio with index=11 is looked up via __get_node_folio(), the synchronous sanity check at page_hit fails with -EFSCORRUPTED and out_err clears uptodate but leaves the dirty bit set from the folio's earlier lifecycle. A subsequent read_node_folio() fails with the same error (footer_nid=0, ino=0), and folio_end_read(folio, false) does not clear dirty either. The writeback iterator then finds the still-dirty folio via the PAGECACHE_TAG_DIRTY tag and submits it. f2fs_write_end_io() observes folio->index=11 with nid_of_node(folio)=0 and panics from softirq context via blk_done_softirq, even though f2fs_sanity_check_node_footer() has already correctly identified the corruption and would have signalled it via its return value. A filesystem inconsistency reachable from a mounted image must not panic the kernel. Mirror the handling already used in f2fs_finish_read_bio(): capture the helper's return value and mark the bio with BLK_STS_IOERR on mismatch instead of issuing BUG_ON. SBI_NEED_FSCK is set by the helper, so fsck.f2fs will repair the inconsistency on the next mount. Reported-by: syzbot+4af46ee83100e99bce09@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09 Fixes: 50ac3ecd8e05 ("f2fs: fix to do sanity check on node footer in {read,write}_end_io") Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com> --- fs/f2fs/data.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 8d4f1e75dee3..c149b0ccf22d 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -382,11 +382,11 @@ static void f2fs_write_end_io(struct bio *bio) STOP_CP_REASON_WRITE_FAIL); } - if (is_node_folio(folio)) { - f2fs_sanity_check_node_footer(sbi, folio, - folio->index, NODE_TYPE_REGULAR, true); - f2fs_bug_on(sbi, folio->index != nid_of_node(folio)); - } + if (is_node_folio(folio) && + f2fs_sanity_check_node_footer(sbi, folio, + folio->index, NODE_TYPE_REGULAR, true)) + bio->bi_status = BLK_STS_IOERR; + if (f2fs_in_warm_node_list(folio)) f2fs_del_fsync_node_entry(sbi, folio); -- 2.43.0 ^ permalink raw reply related [flat|nested] 8+ messages in thread
[parent not found: <20260514233543.9626-1-kartikey406@gmail.com>]
* Re: [syzbot] [f2fs?] kernel BUG in f2fs_write_end_io (2) [not found] <20260514233543.9626-1-kartikey406@gmail.com> @ 2026-05-15 0:07 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-05-15 0:07 UTC (permalink / raw) To: kartikey406, linux-kernel, syzkaller-bugs Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: kernel BUG in f2fs_write_end_io f2fs-dbg: WRITE end_io: index=11 footer_nid=0 ino=0 rc=-117 ------------[ cut here ]------------ kernel BUG at fs/f2fs/data.c:397! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:f2fs_write_end_io+0x193e/0x1970 fs/f2fs/data.c:397 Code: c6 e0 3c 9b 8b e8 02 e5 f6 fc 90 0f 0b e8 8a c9 93 fd 4c 89 e7 48 c7 c6 00 3e 9b 8b e8 eb e4 f6 fc 90 0f 0b e8 73 c9 93 fd 90 <0f> 0b e8 6b c9 93 fd 48 8b 3c 24 48 c7 c6 e0 3c 9b 8b e8 cb e4 f6 RSP: 0018:ffffc90000147b08 EFLAGS: 00010246 RAX: ffffffff8430cfed RBX: 0000000000001000 RCX: ffff88801cee9ec0 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: fffff52000028f11 R12: ffffea0000a312c0 R13: 0000000000001000 R14: 000000000000000b R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126174000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa3d3ae7dac CR3: 0000000037e5c000 CR4: 00000000003526f0 Call Trace: <TASK> blk_update_request+0x57e/0xe60 block/blk-mq.c:1016 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178 blk_complete_reqs block/blk-mq.c:1253 [inline] blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622 run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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:f2fs_write_end_io+0x193e/0x1970 fs/f2fs/data.c:397 Code: c6 e0 3c 9b 8b e8 02 e5 f6 fc 90 0f 0b e8 8a c9 93 fd 4c 89 e7 48 c7 c6 00 3e 9b 8b e8 eb e4 f6 fc 90 0f 0b e8 73 c9 93 fd 90 <0f> 0b e8 6b c9 93 fd 48 8b 3c 24 48 c7 c6 e0 3c 9b 8b e8 cb e4 f6 RSP: 0018:ffffc90000147b08 EFLAGS: 00010246 RAX: ffffffff8430cfed RBX: 0000000000001000 RCX: ffff88801cee9ec0 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: fffff52000028f11 R12: ffffea0000a312c0 R13: 0000000000001000 R14: 000000000000000b R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126174000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa3d3ae7dac CR3: 0000000037e5c000 CR4: 00000000003526f0 Tested on: commit: 66182ca8 Merge tag 'net-7.1-rc4' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10c5e996580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f2e8ebfec4636d32 dashboard link: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=1105e996580000 ^ permalink raw reply [flat|nested] 8+ messages in thread
[parent not found: <20260515005957.13243-1-kartikey406@gmail.com>]
* Re: [syzbot] [f2fs?] kernel BUG in f2fs_write_end_io (2) [not found] <20260515005957.13243-1-kartikey406@gmail.com> @ 2026-05-15 1:37 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-05-15 1:37 UTC (permalink / raw) To: kartikey406, linux-kernel, syzkaller-bugs Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: kernel BUG in f2fs_write_end_io f2fs-dbg: READ end_io: index=3 footer_nid=0 ino=0 uptodate=0 dirty=0 rc=-117 f2fs-dbg: READ end_io: index=3 footer_nid=0 ino=0 uptodate=0 dirty=0 rc=-117 f2fs-dbg: WRITE end_io: index=3 footer_nid=0 ino=0 uptodate=0 dirty=0 rc=-117 ------------[ cut here ]------------ kernel BUG at fs/f2fs/data.c:394! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 42 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: bat_events batadv_bla_periodic_work RIP: 0010:f2fs_write_end_io+0x1a74/0x1ab0 fs/f2fs/data.c:394 Code: c6 20 3d 9b 8b e8 cc d3 f6 fc 90 0f 0b e8 54 c8 93 fd 4c 89 e7 48 c7 c6 20 3d 9b 8b e8 b5 d3 f6 fc 90 0f 0b e8 3d c8 93 fd 90 <0f> 0b e8 35 c8 93 fd 48 8b 7c 24 08 48 c7 c6 20 3d 9b 8b e8 94 d3 RSP: 0018:ffffc90000b47590 EFLAGS: 00010246 RAX: ffffffff8430e123 RBX: 0000000000001000 RCX: ffff88801f2b0000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: fffff52000168e61 R12: ffffea0000951140 R13: 0000000000001000 R14: 0000000000000003 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126274000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000002b72c000 CR4: 00000000003526f0 Call Trace: <TASK> blk_update_request+0x57e/0xe60 block/blk-mq.c:1016 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178 blk_complete_reqs block/blk-mq.c:1253 [inline] blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302 local_bh_enable include/linux/bottom_half.h:33 [inline] netif_rx+0xb9/0xf0 net/core/dev.c:5775 batadv_bla_send_claim+0xa12/0xeb0 net/batman-adv/bridge_loop_avoidance.c:447 batadv_bla_send_announce net/batman-adv/bridge_loop_avoidance.c:675 [inline] batadv_bla_periodic_work+0x629/0xae0 net/batman-adv/bridge_loop_avoidance.c:1490 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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:f2fs_write_end_io+0x1a74/0x1ab0 fs/f2fs/data.c:394 Code: c6 20 3d 9b 8b e8 cc d3 f6 fc 90 0f 0b e8 54 c8 93 fd 4c 89 e7 48 c7 c6 20 3d 9b 8b e8 b5 d3 f6 fc 90 0f 0b e8 3d c8 93 fd 90 <0f> 0b e8 35 c8 93 fd 48 8b 7c 24 08 48 c7 c6 20 3d 9b 8b e8 94 d3 RSP: 0018:ffffc90000b47590 EFLAGS: 00010246 RAX: ffffffff8430e123 RBX: 0000000000001000 RCX: ffff88801f2b0000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: fffff52000168e61 R12: ffffea0000951140 R13: 0000000000001000 R14: 0000000000000003 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126274000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000002b72c000 CR4: 00000000003526f0 Tested on: commit: 66182ca8 Merge tag 'net-7.1-rc4' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=142d20ec580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f2e8ebfec4636d32 dashboard link: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=1400d636580000 ^ permalink raw reply [flat|nested] 8+ messages in thread
[parent not found: <20260515015523.14962-1-kartikey406@gmail.com>]
* Re: [syzbot] [f2fs?] kernel BUG in f2fs_write_end_io (2) [not found] <20260515015523.14962-1-kartikey406@gmail.com> @ 2026-05-15 2:37 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-05-15 2:37 UTC (permalink / raw) To: kartikey406, linux-kernel, syzkaller-bugs Hello, syzbot has tested the proposed patch and the reproducer did not trigger any issue: Reported-by: syzbot+4af46ee83100e99bce09@syzkaller.appspotmail.com Tested-by: syzbot+4af46ee83100e99bce09@syzkaller.appspotmail.com Tested on: commit: 66182ca8 Merge tag 'net-7.1-rc4' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16a0f0c8580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f2e8ebfec4636d32 dashboard link: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=16d3df6c580000 Note: testing is done by a robot and is best-effort only. ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2026-05-15 2:37 UTC | newest]
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2026-05-14 20:19 [syzbot] [f2fs?] kernel BUG in f2fs_write_end_io (2) syzbot
2026-05-14 20:19 ` [f2fs-dev] " syzbot
2026-05-14 23:35 ` Forwarded: [PATCH] f2fs: DEBUG: trace node folio lifecycle to diagnose write_end_io BUG syzbot
2026-05-15 1:00 ` Forwarded: [PATCH] f2fs: DEBUG: full lifecycle trace for node folio write-end-io BUG syzbot
2026-05-15 1:55 ` Forwarded: [PATCH] f2fs: don't BUG on node footer mismatch in f2fs_write_end_io syzbot
[not found] <20260514233543.9626-1-kartikey406@gmail.com>
2026-05-15 0:07 ` [syzbot] [f2fs?] kernel BUG in f2fs_write_end_io (2) syzbot
[not found] <20260515005957.13243-1-kartikey406@gmail.com>
2026-05-15 1:37 ` syzbot
[not found] <20260515015523.14962-1-kartikey406@gmail.com>
2026-05-15 2:37 ` syzbot
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