syzbot


KCSAN: data-race in find_get_block_common / has_bh_in_lru

Status: moderation: reported on 2025/04/26 16:25
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+a4a07f98f629cf636e9e@syzkaller.appspotmail.com
First crash: 378d, last: 1d15h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
128f25fd-1282-4377-92a5-96cbe8babeef assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in find_get_block_common / has_bh_in_lru 2026/01/15 18:44 2026/01/15 18:44 2026/01/15 18:49 a9d6a79219801d2130df3b1a792c57f0e5428e9f

Sample crash report:
loop1: p1 start 134217728 is beyond EOD, truncated
loop1: p2 size 67072 extends beyond EOD, truncated
loop1: p5 size 67072 extends beyond EOD, truncated
==================================================================
BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d277a0 of 8 bytes by task 28934 on cpu 1:
 bh_lru_install fs/buffer.c:1242 [inline]
 find_get_block_common+0x459/0x870 fs/buffer.c:1307
 bdev_getblk+0x4d/0x3f0 include/linux/gfp.h:-1
 __getblk include/linux/buffer_head.h:380 [inline]
 sb_getblk include/linux/buffer_head.h:386 [inline]
 __ext4_get_inode_loc+0x303/0x930 fs/ext4/inode.c:4890
 ext4_get_inode_loc fs/ext4/inode.c:5018 [inline]
 ext4_reserve_inode_write+0xd7/0x250 fs/ext4/inode.c:6372
 __ext4_mark_inode_dirty+0x8c/0x3d0 fs/ext4/inode.c:6550
 ext4_dirty_inode+0x92/0xc0 fs/ext4/inode.c:6587
 __mark_inode_dirty+0x16f/0x710 fs/fs-writeback.c:2623
 generic_update_time fs/inode.c:2192 [inline]
 touch_atime+0x21d/0x330 fs/inode.c:2267
 file_accessed include/linux/fs.h:2264 [inline]
 ext4_file_mmap_prepare+0x13a/0x1a0 fs/ext4/file.c:840
 vfs_mmap_prepare include/linux/fs.h:2076 [inline]
 call_mmap_prepare mm/vma.c:2672 [inline]
 __mmap_region mm/vma.c:2755 [inline]
 mmap_region+0xed6/0x20d0 mm/vma.c:2857
 do_mmap+0x9b2/0xbd0 mm/mmap.c:560
 vm_mmap_pgoff+0x183/0x2d0 mm/util.c:581
 ksys_mmap_pgoff+0x267/0x310 mm/mmap.c:606
 x64_sys_call+0x14df/0x3020 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d277a0 of 8 bytes by task 2983 on cpu 0:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1448
 smp_call_function_many_cond+0x2a7/0xb70 kernel/smp.c:836
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1057
 on_each_cpu_cond include/linux/smp.h:106 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1457
 kill_bdev block/bdev.c:90 [inline]
 blkdev_flush_mapping+0x94/0x1a0 block/bdev.c:720
 blkdev_put_whole block/bdev.c:727 [inline]
 bdev_release+0x2bf/0x3d0 block/bdev.c:1152
 blkdev_release+0x15/0x20 block/fops.c:705
 __fput+0x29b/0x630 fs/file_table.c:510
 fput_close_sync+0xad/0x190 fs/file_table.c:615
 __do_sys_close fs/open.c:1507 [inline]
 __se_sys_close fs/open.c:1492 [inline]
 __x64_sys_close+0x55/0xf0 fs/open.c:1492
 x64_sys_call+0x275d/0x3020 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff8881006fa000 -> 0xffff888107d49958

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2983 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================

Crashes (291):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/08 17:07 upstream 917719c412c4 b2988c17 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/05/08 07:57 upstream fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/05/05 14:11 upstream a293ec25d59d 06e69a27 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/05/05 02:28 upstream c7e4e4d5f7dc a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/05/01 18:40 upstream 26fd6bff2c05 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/27 02:26 upstream 20b64cf8705a 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/25 20:35 upstream 897d54018cc9 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/24 07:36 upstream 45dcf5e28813 9cfb3ca7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/22 01:30 upstream 4ee64205ffaa 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/21 00:06 upstream a5d1079c28a5 e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/16 10:43 upstream aec2f682d47c df15c5f3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/14 13:37 upstream d60bc1401583 362d1323 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/12 13:26 upstream f5459048c38a 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/08 12:54 upstream 3036cd0d3328 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/05 05:59 upstream 3aae9383f42f 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/02 18:15 upstream 5619b098e2fb 91bc79b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/04/01 01:31 upstream dbf00d8d23b4 fb8b2c26 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/03/30 11:54 upstream 7aaa8047eafd dcaebc52 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/03/21 06:47 upstream 42bddab0563f 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/03/20 06:54 upstream 8a30aeb0d1b4 2f245add .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/03/11 09:22 upstream b4f0dd314b39 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/03/09 21:55 upstream 1f318b96cc84 176bead5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/03/05 20:33 upstream c107785c7e8d d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/03/04 20:58 upstream 0031c06807cf e6b6b96b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/03/02 06:41 upstream 39c633261414 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/28 22:10 upstream 2f9339c052bd 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/26 09:43 upstream d9d32e5bd5a4 e0f78d93 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/24 20:38 upstream 7dff99b35460 96b1aa46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/23 18:18 upstream 6de23f81a5e0 6beca497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/17 19:36 upstream d295082ea672 06ec4f7b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/17 07:53 upstream 970296997869 e439b951 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/15 11:09 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/14 14:34 upstream 770aaedb461a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/14 04:25 upstream cee73b1e840c 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/11 16:16 upstream 192c0159402e 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/09 22:55 upstream 05f7e89ab973 4ab09a02 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/06 03:13 upstream 8fdb05de0e2d f03c4191 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/04 19:07 upstream 5fd0a1df5d05 ea10c935 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/04 02:06 upstream de0674d9bc69 42b01fab .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/02/02 00:25 upstream 9f2693489ef8 6b8752f2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/01/29 04:28 upstream 8dfce8991b95 0adc945e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/01/28 19:46 upstream 8dfce8991b95 004c195c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/01/27 17:13 upstream fcb70a56f4d8 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2026/01/13 10:56 upstream b71e635feefc d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
2025/04/26 16:25 upstream f1a3944c860b c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in find_get_block_common / has_bh_in_lru
* Struck through repros no longer work on HEAD.