syzbot


KCSAN: data-race in filemap_read / filemap_read (6)

Status: moderation: reported on 2025/06/15 13:14
Subsystems: fs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+5de889f7f7e25c4e6d5a@syzkaller.appspotmail.com
First crash: 332d, last: 10h44m
✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision Error
c72f5039-c401-427a-8fdf-f8978790ea15 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ KCSAN: data-race in filemap_read / filemap_read (6) 2026/05/13 04:35 2026/05/13 04:35 2026/05/13 04:36 ac1aeadbb84e4988133fcdf26ca80803a538fe09
c5d6563b-eef5-48c3-a468-a225b32796ce repro KCSAN: data-race in filemap_read / filemap_read (6) 2026/03/06 03:01 2026/03/06 03:01 2026/03/06 03:03 31e9c887f7dc24e04b3ca70d0d54fc34141844b0
ffcf09aa-65bd-4fd4-b312-8ab0fe66912a assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in filemap_read / filemap_read (6) 2026/02/24 15:40 2026/02/24 15:40 2026/02/24 16:09 305c0ec5cd886e2d13738e28e1b2df9b0ec20fc9
16a31cf0-47fa-4477-83df-b9c7c032889d assessment-kcsan 🏃 KCSAN: data-race in filemap_read / filemap_read (6) 2026/01/09 13:48 2026/01/09 13:48 533546563b43424f499d2593e18f52d248283b42
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in filemap_read / filemap_read (5) fs 6 1 412d 412d 0/29 auto-obsoleted due to no activity on 2025/05/22 02:24
upstream KCSAN: data-race in filemap_read / filemap_read fs 6 832 903d 1742d 0/29 auto-obsoleted due to no activity on 2023/12/20 06:43
upstream KCSAN: data-race in filemap_read / filemap_read (2) fs 6 2 872d 875d 0/29 auto-obsoleted due to no activity on 2024/01/26 23:06
upstream KCSAN: data-race in filemap_read / filemap_read (3) fs 6 4 779d 813d 0/29 auto-obsoleted due to no activity on 2024/04/29 01:22
upstream KCSAN: data-race in filemap_read / filemap_read (4) fs 6 1 679d 679d 0/29 auto-obsoleted due to no activity on 2024/08/06 15:23

Sample crash report:
==================================================================
BUG: KCSAN: data-race in filemap_read / filemap_read

write to 0xffff88810ad532e0 of 8 bytes by task 11151 on cpu 1:
 filemap_read+0x98d/0xa10 mm/filemap.c:2879
 generic_file_read_iter+0x79/0x330 mm/filemap.c:2998
 ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
 copy_splice_read+0x471/0x6c0 fs/splice.c:362
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x28f/0x670 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x382/0x650 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1433 [inline]
 __se_sys_sendfile64 fs/read_write.c:1419 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1419
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 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

write to 0xffff88810ad532e0 of 8 bytes by task 11130 on cpu 0:
 filemap_read+0x98d/0xa10 mm/filemap.c:2879
 generic_file_read_iter+0x79/0x330 mm/filemap.c:2998
 ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
 copy_splice_read+0x471/0x6c0 fs/splice.c:362
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x28f/0x670 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x382/0x650 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1433 [inline]
 __se_sys_sendfile64 fs/read_write.c:1419 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1419
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 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: 0x00000000000002be -> 0x00000000000002bf

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11130 Comm: syz.7.2036 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================

Crashes (563):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/13 03:34 upstream c21b90f77687 a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/12 09:38 upstream 50897c955902 07aeade5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/11 13:06 upstream 5d6919055dec 845acb1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/10 23:13 upstream 5d6919055dec 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/10 12:21 upstream 1bfaee9d3351 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/09 17:11 upstream 27a26ccfd528 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/08 18:08 upstream 917719c412c4 b2988c17 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/08 05:40 upstream fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/07 18:52 upstream 8ab992f815d6 cbf9e0fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/07 04:43 upstream 5862221fdded f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/05 11:06 upstream a293ec25d59d 06e69a27 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/03 19:46 upstream f377d0025eb0 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/03 03:35 upstream 66edb901bf87 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/01 19:44 upstream 6fe0be6dc7fa 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/05/01 06:27 upstream 26fd6bff2c05 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/30 15:42 upstream e75a43c7cec4 a7464baf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/30 02:42 upstream 57b8e2d666a3 005438fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/29 15:32 upstream 57b8e2d666a3 7ca9e4d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/28 23:15 upstream dca922e019dd 95008c03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/28 16:54 upstream dca922e019dd ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/28 12:16 upstream 3b3bea6d4b9c ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/27 21:27 upstream 254f49634ee1 ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/27 15:50 upstream 254f49634ee1 0f700595 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/27 02:04 upstream 20b64cf8705a 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/26 04:40 upstream 897d54018cc9 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/25 03:41 upstream 27d128c1cff6 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/20 07:10 upstream c1f49dea2b8f 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/19 16:31 upstream faeab166167f 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/19 05:59 upstream eb5249b12507 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/17 12:52 upstream 3cd8b194bf34 de0a551d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
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 filemap_read / filemap_read
2026/04/15 20:14 upstream 1f5ffc672165 c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/13 11:36 upstream 028ef9c96e96 9530ccf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/13 02:44 upstream 028ef9c96e96 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/12 11:26 upstream f5459048c38a 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/12 03:54 upstream e753c16cb3dd 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/11 15:26 upstream e774d5f1bc27 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/10 19:48 upstream 7c6c4ed80b87 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/10 06:36 upstream 9a9c8ce300cd 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/09 16:52 upstream 8b02520ec5f7 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/09 07:26 upstream 7f87a5ea75f0 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/08 21:51 upstream 7f87a5ea75f0 d9b7f621 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/08 16:16 upstream 3036cd0d3328 d9b7f621 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/04/08 09:14 upstream 3036cd0d3328 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/03/02 14:23 upstream 11439c4635ed b9dd6534 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/02/22 21:08 upstream 32a92f8c8932 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2026/01/09 06:44 upstream 623fb9912f6a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
2025/06/15 13:13 upstream 8c6bc74c7f89 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / filemap_read
* Struck through repros no longer work on HEAD.