syzbot


KCSAN: data-race in filemap_splice_read / filemap_splice_read

Status: moderation: reported on 2023/12/07 10:14
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+656c0f7422b03843b487@syzkaller.appspotmail.com
First crash: 902d, last: 1d23h

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

write to 0xffff888100b336a8 of 8 bytes by task 3534 on cpu 0:
 filemap_splice_read+0x4f4/0x740 mm/filemap.c:3125
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26f/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff888100b336a8 of 8 bytes by task 3539 on cpu 1:
 filemap_splice_read+0x4f4/0x740 mm/filemap.c:3125
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26f/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000002b1b -> 0x0000000000002b24

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3539 Comm: syz.4.15 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================
syz.4.15: attempt to access beyond end of device
loop4: rw=8390657, sector=128, nr_sectors = 1 limit=128
Buffer I/O error on dev loop4, logical block 128, lost async page write

Crashes (1404):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/14 09:17 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/13 19:36 upstream 9d9c1cfec01c d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/13 11:00 upstream 9551a26f17d9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/12 18:04 upstream 187d0801404f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/11 21:51 upstream d358e5254674 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/11 03:44 upstream 0048fbb4011e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/10 13:55 upstream c9b47175e913 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/09 19:19 upstream cb015814f8b6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/09 05:45 upstream cfd4039213e7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/08 16:30 upstream c2f2b01b74be d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/08 03:10 upstream ba65a4e7120a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/07 13:44 upstream 37bb2e7217b0 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/07 00:11 upstream cc3ee4ba57b7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/06 15:36 upstream 416f99c3b16f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/05 20:59 upstream d1d36025a617 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/05 13:14 upstream 2061f18ad76e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/04 23:29 upstream 559e608c4655 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/04 04:54 upstream 8f7aa3d3c732 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/03 23:50 upstream 3f9f0252130e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/03 08:08 upstream d61f1cc5db79 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/02 13:33 upstream 4a26e7032d7d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/02 01:04 upstream 1d18101a644e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/12/01 07:34 upstream 7d0a66e4bb90 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/30 20:24 upstream e69c7c175115 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/30 01:43 upstream 6bda50f4333f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/28 14:26 upstream e538109ac71d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/28 02:59 upstream e1afacb68573 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/27 14:15 upstream 765e56e41a5a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/26 22:49 upstream 4941a17751c9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/26 15:57 upstream 30f09200cc4a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/26 09:37 upstream 30f09200cc4a 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/25 20:47 upstream 8a2bcda5e139 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/25 02:19 upstream ac3fd01e4c1e 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/24 12:56 upstream ac3fd01e4c1e bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/24 01:54 upstream d0e88704d96c 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/23 10:51 upstream d13f3ac64efb 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/22 22:13 upstream 89edd36fd801 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/21 22:40 upstream 2eba5e05d9bc 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/21 06:00 upstream 8e621c9a3375 2cc4c24a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/20 11:50 upstream 23cb64fb7625 2cc4c24a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/19 22:26 upstream 23cb64fb7625 26ee5237 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/19 17:16 upstream 8b690556d8fe 26ee5237 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/19 07:30 upstream 8b690556d8fe ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2025/11/18 21:50 upstream 5bebe8de1926 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2023/12/06 14:46 upstream bee0e7762ad2 e3299f55 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
2023/11/28 11:10 upstream df60cee26a2e 9fe51b7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in filemap_splice_read / filemap_splice_read
* Struck through repros no longer work on HEAD.