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KCSAN: data-race in __io_sqe_files_scm / unix_inflight

Status: auto-closed as invalid on 2020/03/19 03:26
Subsystems: fs
[Documentation on labels]
First crash: 1566d, last: 1566d

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

read to 0xffff8880ad8c8e28 of 8 bytes by task 5159 on cpu 0:
 __io_sqe_files_scm+0x3f3/0x4e0 fs/io_uring.c:3844
 io_sqe_files_scm fs/io_uring.c:3907 [inline]
 io_sqe_files_register fs/io_uring.c:4039 [inline]
 __io_uring_register+0x1afe/0x2070 fs/io_uring.c:5162
 __do_sys_io_uring_register fs/io_uring.c:5214 [inline]
 __se_sys_io_uring_register fs/io_uring.c:5196 [inline]
 __x64_sys_io_uring_register+0x14e/0x2d0 fs/io_uring.c:5196
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880ad8c8e28 of 8 bytes by task 5160 on cpu 1:
 unix_inflight+0x1b0/0x200 net/unix/scm.c:64
 __io_sqe_files_scm+0x232/0x4e0 fs/io_uring.c:3870
 io_sqe_files_scm fs/io_uring.c:3907 [inline]
 io_sqe_files_register fs/io_uring.c:4039 [inline]
 __io_uring_register+0x1afe/0x2070 fs/io_uring.c:5162
 __do_sys_io_uring_register fs/io_uring.c:5214 [inline]
 __se_sys_io_uring_register fs/io_uring.c:5196 [inline]
 __x64_sys_io_uring_register+0x14e/0x2d0 fs/io_uring.c:5196
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5160 Comm: syz-executor.1 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 5160 Comm: syz-executor.1 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x11d/0x181 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xd kernel/kcsan/report.c:313
 kcsan_setup_watchpoint+0x3fe/0x460 kernel/kcsan/core.c:416
 check_access kernel/kcsan/core.c:459 [inline]
 __tsan_unaligned_write8+0xc7/0x110 kernel/kcsan/core.c:589
 unix_inflight+0x1b0/0x200 net/unix/scm.c:64
 __io_sqe_files_scm+0x232/0x4e0 fs/io_uring.c:3870
 io_sqe_files_scm fs/io_uring.c:3907 [inline]
 io_sqe_files_register fs/io_uring.c:4039 [inline]
 __io_uring_register+0x1afe/0x2070 fs/io_uring.c:5162
 __do_sys_io_uring_register fs/io_uring.c:5214 [inline]
 __se_sys_io_uring_register fs/io_uring.c:5196 [inline]
 __x64_sys_io_uring_register+0x14e/0x2d0 fs/io_uring.c:5196
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45af49
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2b5bf91c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045af49
RDX: 00000000200010c0 RSI: 0000000000000002 RDI: 0000000000000014
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 40000000000001d4 R11: 0000000000000246 R12: 00007f2b5bf926d4
R13: 00000000004d09b8 R14: 00000000004d8aa0 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/01/09 03:24 https://github.com/google/ktsan.git kcsan 245a43005292 ddc3e859 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.