WARNING in btrfs_add_link (2)

Status: upstream: reported C repro on 2024/07/27 06:25
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+4f8497100604a77814fe@syzkaller.appspotmail.com
First crash: 814d, last: 1d18h
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2024/07/27 linux-5.15.y (ToT) 7e89efd3ae1c C [report] WARNING in btrfs_add_link
2024/07/27 upstream (ToT) 3a7e02c040b1 C Didn't crash
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in btrfs_add_link (3) prio:high btrfs -1 5 22d 51d 0/29 upstream: reported on 2026/08/29 06:51
upstream WARNING in btrfs_add_link btrfs -1 syz, C error unreliable 7 1442d 1462d 0/29 auto-obsoleted due to no activity on 2023/07/21 23:31
upstream WARNING in btrfs_add_link (2) btrfs -1 1 241d 237d 0/29 auto-obsoleted due to no activity on 2026/05/30 22:47
linux-6.1 WARNING in btrfs_add_link -1 1 17d 17d 0/3 upstream: reported on 2026/10/02 14:54
linux-5.15 WARNING in btrfs_add_link -1 1 1270d 1270d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:04
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/10/17 23:50 16m retest repro linux-5.15.y report job log log
2026/10/17 23:50 13m retest repro linux-5.15.y report job log log
2026/08/16 04:35 15m retest repro linux-5.15.y report job log log
2026/08/16 04:35 15m retest repro linux-5.15.y report job log log
2026/08/16 04:35 13m retest repro linux-5.15.y report job log log
2026/07/13 01:22 16m retest repro linux-5.15.y report log
2026/05/31 04:08 22m retest repro linux-5.15.y report log
2026/05/31 04:08 22m retest repro linux-5.15.y report log
2026/05/31 04:08 21m retest repro linux-5.15.y report log
2026/04/20 07:13 15m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (10)
Created Duration User Patch Repo Result
2026/03/27 01:30 1m fix candidate upstream error job log
2026/02/24 19:52 11m fix candidate upstream error job log
2026/01/25 09:57 1m fix candidate upstream error job log
2025/11/30 19:02 3m fix candidate upstream error job log
2025/10/31 04:30 1m fix candidate upstream error job log
2025/06/30 20:02 11m fix candidate upstream error job log
2025/03/31 00:34 9m fix candidate upstream error job log
2025/01/12 20:58 11m fix candidate upstream error job log
2024/10/24 07:27 1m fix candidate upstream error job log
2024/09/30 02:35 1m bisect fix linux-5.15.y error job log

Sample crash report:
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4019 at fs/btrfs/inode.c:6761 btrfs_add_link+0x7ac/0xbcc fs/btrfs/inode.c:6761
Modules linked in:
CPU: 0 PID: 4019 Comm: syz-executor364 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : btrfs_add_link+0x7ac/0xbcc fs/btrfs/inode.c:6761
lr : btrfs_add_link+0x7ac/0xbcc fs/btrfs/inode.c:6761
sp : ffff80001d697940
x29: ffff80001d697a40 x28: 0000000000000100 x27: 0000000000000107
x26: 00000000fffffff4 x25: 0000000000000001 x24: ffff700003ad2f30
x23: dfff800000000000 x22: 00000000fffffff4 x21: ffff0000deebf210
x20: 1fffe0001bdd7e4d x19: ffff0000deebf268 x18: 0000000000000001
x17: 0000000000000000 x16: ffff800011b4e3fc x15: 00000000ffffffff
x14: ffff0000ca52d1c0 x13: 0000000000000001 x12: 0000000000000001
x11: 0000000000000000 x10: 0000000000000000 x9 : 5e7dc225e8eede00
x8 : 5e7dc225e8eede00 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80001d6970b8 x4 : ffff800014c50660 x3 : ffff8000085568c0
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000026
Call trace:
 btrfs_add_link+0x7ac/0xbcc fs/btrfs/inode.c:6761
 btrfs_add_nondir fs/btrfs/inode.c:6812 [inline]
 btrfs_link+0x3a0/0x678 fs/btrfs/inode.c:6994
 vfs_link+0x598/0x74c fs/namei.c:4557
 do_linkat+0x2f4/0x898 fs/namei.c:4628
 __do_sys_linkat fs/namei.c:4656 [inline]
 __se_sys_linkat fs/namei.c:4653 [inline]
 __arm64_sys_linkat+0xe4/0x100 fs/namei.c:4653
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
irq event stamp: 212540
hardirqs last  enabled at (212539): [<ffff80000832c1b4>] __up_console_sem+0xb4/0x100 kernel/printk/printk.c:257
hardirqs last disabled at (212540): [<ffff800011b49ab0>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396
softirqs last  enabled at (212520): [<ffff8000081b6920>] softirq_handle_end kernel/softirq.c:401 [inline]
softirqs last  enabled at (212520): [<ffff8000081b6920>] handle_softirqs+0xb88/0xdbc kernel/softirq.c:586
softirqs last disabled at (212435): [<ffff8000081b6fb8>] __do_softirq kernel/softirq.c:592 [inline]
softirqs last disabled at (212435): [<ffff8000081b6fb8>] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline]
softirqs last disabled at (212435): [<ffff8000081b6fb8>] invoke_softirq kernel/softirq.c:439 [inline]
softirqs last disabled at (212435): [<ffff8000081b6fb8>] __irq_exit_rcu+0x268/0x4d8 kernel/softirq.c:641
---[ end trace d447eb9a491351bc ]---
BTRFS: error (device loop0) in btrfs_add_link:6761: errno=-12 Out of memory
BTRFS info (device loop0): forced readonly

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/08 15:08 linux-5.15.y c16c81c81336 7e3bd60d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan-arm64 WARNING in btrfs_add_link
2024/07/27 09:24 linux-5.15.y 7c6d66f0266f 46eb10b7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan-arm64 WARNING in btrfs_add_link
2024/07/27 08:31 linux-5.15.y 7c6d66f0266f 46eb10b7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan-arm64 WARNING in btrfs_add_link
2024/07/27 07:31 linux-5.15.y 7c6d66f0266f 46eb10b7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan-arm64 WARNING in btrfs_add_link
2026/09/02 06:30 linux-5.15.y 28c35638ec51 587f6b29 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan WARNING in btrfs_add_link
2026/09/02 05:34 linux-5.15.y 28c35638ec51 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in btrfs_add_link
2025/03/30 17:00 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in btrfs_add_link
2025/03/08 14:37 linux-5.15.y c16c81c81336 7e3bd60d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in btrfs_add_link
2024/08/21 23:18 linux-5.15.y fa93fa65db6e db5852f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in btrfs_add_link
2024/07/27 06:24 linux-5.15.y 7c6d66f0266f 46eb10b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in btrfs_add_link
* Struck through repros no longer work on HEAD.