syzbot


KCSAN: data-race in __close_fd / do_select

Status: auto-closed as invalid on 2020/12/24 20:13
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+62cf6c87aedb4531776e@syzkaller.appspotmail.com
First crash: 1250d, last: 1250d

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

write to 0xffff888109c77600 of 8 bytes by task 18278 on cpu 0:
 instrument_write include/linux/instrumented.h:42 [inline]
 __clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:42 [inline]
 __clear_open_fd fs/file.c:253 [inline]
 __put_unused_fd fs/file.c:572 [inline]
 pick_file fs/file.c:655 [inline]
 __close_fd+0xcd/0x190 fs/file.c:669
 __do_sys_close fs/open.c:1295 [inline]
 __se_sys_close fs/open.c:1293 [inline]
 __x64_sys_close+0x39/0x90 fs/open.c:1293
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888109c77600 of 8 bytes by task 18279 on cpu 1:
 max_select_fd fs/select.c:446 [inline]
 do_select+0x28d/0xf30 fs/select.c:487
 core_sys_select+0x41f/0x670 fs/select.c:677
 do_pselect fs/select.c:759 [inline]
 __do_sys_pselect6+0x1bf/0x220 fs/select.c:800
 __se_sys_pselect6 fs/select.c:791 [inline]
 __x64_sys_pselect6+0x74/0x80 fs/select.c:791
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18279 Comm: syz-executor.4 Not tainted 5.10.0-rc4-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: 18279 Comm: syz-executor.4 Not tainted 5.10.0-rc4-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+0x116/0x15d lib/dump_stack.c:118
 panic+0x1e7/0x5fa kernel/panic.c:231
 kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
 kcsan_setup_watchpoint+0x46a/0x4d0 kernel/kcsan/core.c:568
 max_select_fd fs/select.c:446 [inline]
 do_select+0x28d/0xf30 fs/select.c:487
 core_sys_select+0x41f/0x670 fs/select.c:677
 do_pselect fs/select.c:759 [inline]
 __do_sys_pselect6+0x1bf/0x220 fs/select.c:800
 __se_sys_pselect6 fs/select.c:791 [inline]
 __x64_sys_pselect6+0x74/0x80 fs/select.c:791
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: 0d b4 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc651367c78 EFLAGS: 00000246 ORIG_RAX: 000000000000010e
RAX: ffffffffffffffda RBX: 0000000000025fc0 RCX: 000000000045deb9
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000040
RBP: 000000000118bf78 R08: 0000000020000200 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffea136035f R14: 00007fc6513689c0 R15: 000000000118bf2c
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
2020/11/19 20:12 upstream 131ad0b6f529 0767f13f .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.