syzbot


kernel BUG in xfs_buf_free

Status: upstream: reported on 2026/07/15 08:03
Subsystems: xfs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+94c22d92f72f5a235b7d@syzkaller.appspotmail.com
First crash: 4d23h, last: 17h59m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
f61fefcc-9bf3-4002-9062-efaba882f596 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ kernel BUG in xfs_buf_free 2026/07/13 01:02 2026/07/13 01:02 2026/07/13 01:59 d78ea535f456172a095a6d211ee0a2de1d049968

			
		
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [xfs?] kernel BUG in xfs_buf_free 0 (1) 2026/07/15 08:03

Sample crash report:
XFS (loop0): First 128 bytes of corrupted metadata buffer:
00000000: 53 55 4d 59 00 00 00 02 ff ff ff ff ff ff ff ff  SUMY............
00000010: 00 00 00 00 00 00 00 04 00 00 20 00 00 00 00 40  .......... ....@
00000020: 9f 91 83 2a 3b 79 45 c3 9d 6d ed 0b c7 35 7f e4  ...*;yE..m...5..
00000030: 00 00 00 00 25 47 cc 81 00 00 00 0d 00 00 00 03  ....%G..........
00000040: 00 00 0e a8 00 00 11 58 00 00 00 00 00 00 00 00  .......X........
00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
XFS (loop0): metadata I/O error in "xfs_btree_read_buf_block+0x2ae/0x4a0" at daddr 0x4 len 4 error 74
FAULT_INJECTION: forcing a failure.
name fail_page_alloc, interval 1, probability 0, space 0, times 1
CPU: 0 UID: 0 PID: 5337 Comm: syz.0.0 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
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x40c/0x560 lib/fault-inject.c:174
 prepare_alloc_pages+0x230/0x650 mm/page_alloc.c:5055
 __alloc_frozen_pages_noprof+0x12f/0x380 mm/page_alloc.c:5293
 alloc_pages_mpol+0x212/0x380 mm/mempolicy.c:2490
 folio_alloc_mpol_noprof+0x39/0x160 mm/mempolicy.c:2509
 shmem_alloc_folio mm/shmem.c:1907 [inline]
 shmem_alloc_and_add_folio+0x43e/0xf60 mm/shmem.c:1949
 shmem_get_folio_gfp+0x5da/0x16d0 mm/shmem.c:2502
 shmem_get_folio+0x86/0xb0 mm/shmem.c:2608
 xmbuf_map_backing_mem+0x1c4/0x590 fs/xfs/xfs_buf_mem.c:144
 xfs_buf_alloc_backing_mem fs/xfs/xfs_buf.c:216 [inline]
 xfs_buf_alloc+0xafe/0x19b0 fs/xfs/xfs_buf.c:322
 xfs_buf_find_insert+0x50/0x14e0 fs/xfs/xfs_buf.c:483
 xfs_buf_get_map+0x120f/0x17a0 fs/xfs/xfs_buf.c:584
 xfs_buf_get fs/xfs/xfs_buf.h:233 [inline]
 xfbtree_init_leaf_block+0x117/0x4a0 fs/xfs/libxfs/xfs_btree_mem.c:94
 xfbtree_init+0x1b6/0x450 fs/xfs/libxfs/xfs_btree_mem.c:147
 xrep_rmap_setup_scan+0xfb/0x1f0 fs/xfs/scrub/rmap_repair.c:1658
 xrep_rmapbt+0x3c/0xb0 fs/xfs/scrub/rmap_repair.c:1709
 xrep_attempt+0x184/0x7c0 fs/xfs/scrub/repair.c:78
 xfs_scrub_metadata+0xce4/0x1910 fs/xfs/scrub/scrub.c:747
 xfs_ioc_scrubv_metadata+0x7ac/0xb70 fs/xfs/scrub/scrub.c:981
 xfs_file_ioctl+0x916/0x1590 fs/xfs/xfs_ioctl.c:1308
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbba3d9de59
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:00007fbba4bcbfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fbba4026090 RCX: 00007fbba3d9de59
RDX: 0000200000000000 RSI: 00000000c0285840 RDI: 0000000000000005
RBP: 00007fbba4bcc050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007fbba4026128 R14: 00007fbba4026090 R15: 00007ffef691ced8
 </TASK>
------------[ cut here ]------------
kernel BUG at arch/x86/mm/physaddr.c:28!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5337 Comm: syz.0.0 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
RIP: 0010:__phys_addr+0xf7/0x100 arch/x86/mm/physaddr.c:28
Code: c7 c9 8f 57 90 e8 49 e1 bc 00 eb 8b 48 c7 c7 f0 0f 9c 8e 48 89 de 48 89 ca 49 89 ce e8 52 de 98 03 4c 89 f1 e9 7b ff ff ff 90 <0f> 0b 90 0f 0b 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000f8d7150 EFLAGS: 00010206
RAX: 1ffffffff1c9e7e0 RBX: 0000778000000000 RCX: 0000000000000000
RDX: ffff888000190000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff9057a5f7 R09: 1ffffffff20af4be
R10: dffffc0000000000 R11: fffffbfff20af4bf R12: ffffea0000000000
R13: dffffc0000000000 R14: 0000000080000000 R15: dffffc0000000000
FS:  00007fbba4bcc6c0(0000) GS:ffff88808c54a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbba4bcbff8 CR3: 00000000122c4000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 virt_to_folio include/linux/mm.h:1944 [inline]
 xfs_buf_free+0x25a/0x510 fs/xfs/xfs_buf.c:118
 xfs_buf_alloc+0xc93/0x19b0 fs/xfs/xfs_buf.c:324
 xfs_buf_find_insert+0x50/0x14e0 fs/xfs/xfs_buf.c:483
 xfs_buf_get_map+0x120f/0x17a0 fs/xfs/xfs_buf.c:584
 xfs_buf_get fs/xfs/xfs_buf.h:233 [inline]
 xfbtree_init_leaf_block+0x117/0x4a0 fs/xfs/libxfs/xfs_btree_mem.c:94
 xfbtree_init+0x1b6/0x450 fs/xfs/libxfs/xfs_btree_mem.c:147
 xrep_rmap_setup_scan+0xfb/0x1f0 fs/xfs/scrub/rmap_repair.c:1658
 xrep_rmapbt+0x3c/0xb0 fs/xfs/scrub/rmap_repair.c:1709
 xrep_attempt+0x184/0x7c0 fs/xfs/scrub/repair.c:78
 xfs_scrub_metadata+0xce4/0x1910 fs/xfs/scrub/scrub.c:747
 xfs_ioc_scrubv_metadata+0x7ac/0xb70 fs/xfs/scrub/scrub.c:981
 xfs_file_ioctl+0x916/0x1590 fs/xfs/xfs_ioctl.c:1308
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbba3d9de59
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:00007fbba4bcbfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fbba4026090 RCX: 00007fbba3d9de59
RDX: 0000200000000000 RSI: 00000000c0285840 RDI: 0000000000000005
RBP: 00007fbba4bcc050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007fbba4026128 R14: 00007fbba4026090 R15: 00007ffef691ced8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__phys_addr+0xf7/0x100 arch/x86/mm/physaddr.c:28
Code: c7 c9 8f 57 90 e8 49 e1 bc 00 eb 8b 48 c7 c7 f0 0f 9c 8e 48 89 de 48 89 ca 49 89 ce e8 52 de 98 03 4c 89 f1 e9 7b ff ff ff 90 <0f> 0b 90 0f 0b 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000f8d7150 EFLAGS: 00010206
RAX: 1ffffffff1c9e7e0 RBX: 0000778000000000 RCX: 0000000000000000
RDX: ffff888000190000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff9057a5f7 R09: 1ffffffff20af4be
R10: dffffc0000000000 R11: fffffbfff20af4bf R12: ffffea0000000000
R13: dffffc0000000000 R14: 0000000080000000 R15: dffffc0000000000
FS:  00007fbba4bcc6c0(0000) GS:ffff88808c54a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f11087395a3 CR3: 00000000122c4000 CR4: 0000000000352ef0

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/15 13:02 upstream 58717b2a1365 a4ed0f4f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in xfs_buf_free
2026/07/14 02:41 upstream 0f26556c5eee 2130f682 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in xfs_buf_free
2026/07/14 02:40 upstream 0f26556c5eee 2130f682 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in xfs_buf_free
2026/07/13 12:07 upstream a13c140cc289 a870962e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in xfs_buf_free
2026/07/12 08:15 upstream 44696aa3a489 d78ea535 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in xfs_buf_free
2026/07/12 03:18 upstream dd3210c47e8d d78ea535 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in xfs_buf_free
2026/07/11 08:00 upstream 61c03dfde854 d78ea535 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in xfs_buf_free
* Struck through repros no longer work on HEAD.