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KCSAN: data-race in do_splice / ksys_write

Status: closed as invalid on 2019/11/19 13:54
Subsystems: fs
[Documentation on labels]
First crash: 1633d, last: 1633d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_splice / ksys_write (3) fs 1 541d 541d 0/26 auto-obsoleted due to no activity on 2022/12/06 21:10
upstream KCSAN: data-race in do_splice / ksys_write (2) fs 1 1279d 1279d 0/26 auto-closed as invalid on 2020/11/29 01:06

Sample crash report:
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
==================================================================
BUG: KCSAN: data-race in do_splice / ksys_write

write to 0xffff888122d45068 of 8 bytes by task 15042 on cpu 0:
 do_splice+0xb2e/0xbe0 fs/splice.c:1189
 __do_sys_splice fs/splice.c:1425 [inline]
 __se_sys_splice fs/splice.c:1405 [inline]
 __x64_sys_splice+0x20a/0x220 fs/splice.c:1405
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888122d45068 of 8 bytes by task 15046 on cpu 1:
 ksys_write+0x101/0x1b0 fs/read_write.c:613
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15046 Comm: syz-executor.0 Not tainted 5.4.0-rc6+ #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: 15046 Comm: syz-executor.0 Not tainted 5.4.0-rc6+ #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+0xf5/0x159 lib/dump_stack.c:113
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xe kernel/kcsan/report.c:302
 kcsan_setup_watchpoint+0x3fe/0x410 kernel/kcsan/core.c:357
 check_access kernel/kcsan/core.c:409 [inline]
 __tsan_unaligned_write8+0x143/0x1f0 kernel/kcsan/core.c:530
 ksys_write+0x101/0x1b0 fs/read_write.c:613
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a219
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:00007f254cd2bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a219
RDX: 0000000000000024 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f254cd2c6d4
R13: 00000000004c6cf5 R14: 00000000004e2238 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
2019/11/06 06:50 https://github.com/google/ktsan.git kcsan 94c006602e13 bc2c6e45 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.