syzbot


KCSAN: data-race in shmem_getattr / shmem_recalc_inode

Status: moderation: reported on 2024/07/04 23:41
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+dfb578404df369f6599b@syzkaller.appspotmail.com
First crash: 99d, last: 4d13h

Sample crash report:
BUG: KCSAN: data-race in shmem_getattr / shmem_recalc_inode

read-write to 0xffff888115e89750 of 8 bytes by task 5020 on cpu 0:
 shmem_recalc_inode+0x36/0x1b0 mm/shmem.c:437
 shmem_alloc_and_add_folio mm/shmem.c:1871 [inline]
 shmem_get_folio_gfp+0x7ce/0xd90 mm/shmem.c:2335
 shmem_get_folio mm/shmem.c:2441 [inline]
 shmem_write_begin+0xa2/0x180 mm/shmem.c:3046
 generic_perform_write+0x1a8/0x4a0 mm/filemap.c:4054
 shmem_file_write_iter+0xc2/0xe0 mm/shmem.c:3221
 __kernel_write_iter+0x24b/0x4e0 fs/read_write.c:616
 dump_emit_page fs/coredump.c:884 [inline]
 dump_user_range+0x3a7/0x550 fs/coredump.c:945
 elf_core_dump+0x1b66/0x1c60 fs/binfmt_elf.c:2121
 do_coredump+0x1736/0x1ce0 fs/coredump.c:758
 get_signal+0xdc0/0x1070 kernel/signal.c:2902
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0x9a/0x130 kernel/entry/common.c:231
 irqentry_exit+0x12/0x50 kernel/entry/common.c:334
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffff888115e89750 of 8 bytes by task 3267 on cpu 1:
 shmem_getattr+0x42/0x200 mm/shmem.c:1157
 vfs_getattr_nosec fs/stat.c:166 [inline]
 vfs_getattr+0x19b/0x1e0 fs/stat.c:207
 vfs_statx_path fs/stat.c:251 [inline]
 vfs_statx+0x134/0x2f0 fs/stat.c:315
 vfs_fstatat+0xec/0x110 fs/stat.c:341
 __do_sys_newfstatat fs/stat.c:505 [inline]
 __se_sys_newfstatat+0x58/0x260 fs/stat.c:499
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:499
 x64_sys_call+0x141f/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:263
 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: 0x0000000000000e81 -> 0x0000000000000e84

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3267 Comm: syz-executor Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================

Crashes (18):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/08 02:25 upstream 87d6aab2389e d7906eff .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/10/04 08:16 upstream 0c559323bbaa d7906eff .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/09/26 15:12 upstream 11a299a7933e 0d19f247 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/09/25 19:48 upstream 684a64bf32b6 349a68c4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/09/24 04:43 upstream 18ba6034468e 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/09/12 23:52 upstream fdf042df0463 60e1a995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/09/05 16:09 upstream c763c4339688 464ac2ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/08/20 23:00 upstream 521b1e7f4cf0 9f0ab3fb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/08/18 07:18 upstream 810996a36309 dbc93b08 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/08/16 13:40 upstream d7a5aa4b3c00 e1c76ab2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/08/13 12:36 upstream d74da846046a 7b0f4b46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/08/09 12:02 upstream ee9a43b7cfe2 a83d9288 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/07/31 17:53 upstream e4fc196f5ba3 6fde257d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/07/27 00:50 upstream 2f8c4f506285 46eb10b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/07/17 05:52 upstream 0434dbe32053 215bec2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/07/13 11:08 upstream 528dd46d0fc3 eaeb5c15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/07/10 14:03 upstream 34afb82a3c67 bc144f9a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
2024/07/04 23:41 upstream 661e504db04c 3f2748a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shmem_getattr / shmem_recalc_inode
* Struck through repros no longer work on HEAD.