syzbot


KCSAN: data-race in filemap_read / filemap_read (4)

Status: moderation: reported on 2024/07/02 15:23
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+c2cba7c5a31e3d3b39ff@syzkaller.appspotmail.com
First crash: 10d, last: 10d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in filemap_read / filemap_read fs 832 234d 1073d 0/27 auto-obsoleted due to no activity on 2023/12/20 06:43
upstream KCSAN: data-race in filemap_read / filemap_read (2) fs 2 203d 206d 0/27 auto-obsoleted due to no activity on 2024/01/26 23:06
upstream KCSAN: data-race in filemap_read / filemap_read (3) fs 4 110d 144d 0/27 auto-obsoleted due to no activity on 2024/04/29 01:22

Sample crash report:
loop1: detected capacity change from 0 to 1024
==================================================================
BUG: KCSAN: data-race in filemap_read / filemap_read

read to 0xffff88810f790790 of 8 bytes by task 5172 on cpu 0:
 filemap_read+0x89/0x690 mm/filemap.c:2601
 generic_file_read_iter+0x78/0x340 mm/filemap.c:2806
 ext4_file_read_iter+0x1d8/0x2a0
 do_iter_readv_writev+0x339/0x3e0
 vfs_readv+0x1e5/0x660 fs/read_write.c:932
 do_preadv fs/read_write.c:1049 [inline]
 __do_sys_preadv2 fs/read_write.c:1111 [inline]
 __se_sys_preadv2+0x10c/0x1d0 fs/read_write.c:1102
 __x64_sys_preadv2+0x78/0x90 fs/read_write.c:1102
 x64_sys_call+0x1a63/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:328
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff88810f790790 of 8 bytes by task 5171 on cpu 1:
 filemap_read+0x615/0x690 mm/filemap.c:2694
 generic_file_read_iter+0x78/0x340 mm/filemap.c:2806
 ext4_file_read_iter+0x1d8/0x2a0
 do_iter_readv_writev+0x339/0x3e0
 vfs_readv+0x1e5/0x660 fs/read_write.c:932
 do_preadv fs/read_write.c:1049 [inline]
 __do_sys_preadv2 fs/read_write.c:1111 [inline]
 __se_sys_preadv2+0x10c/0x1d0 fs/read_write.c:1102
 __x64_sys_preadv2+0x78/0x90 fs/read_write.c:1102
 x64_sys_call+0x1a63/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:328
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffffffffffffff -> 0x0000000000000016

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5171 Comm: syz.1.470 Not tainted 6.10.0-rc6-syzkaller-00051-g1dfe225e9af5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/07/02 15:23 upstream 1dfe225e9af5 07f0a0a0 .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.