syzbot


KCSAN: data-race in __kernel_write_iter / set_task_ioprio

Status: moderation: reported on 2024/10/22 19:04
Subsystems: block
[Documentation on labels]
Reported-by: syzbot+cf58a5c9bd44f4f17a33@syzkaller.appspotmail.com
First crash: 44d, last: 22d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __kernel_write_iter / set_task_ioprio

write to 0xffff88810a569938 of 8 bytes by task 14875 on cpu 1:
 set_task_ioprio+0x240/0x260 block/blk-ioc.c:287
 __do_sys_ioprio_set block/ioprio.c:125 [inline]
 __se_sys_ioprio_set+0x246/0x580 block/ioprio.c:69
 __x64_sys_ioprio_set+0x43/0x50 block/ioprio.c:69
 x64_sys_call+0x2bcf/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:252
 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

read to 0xffff88810a569938 of 8 bytes by task 14870 on cpu 0:
 __get_task_ioprio include/linux/ioprio.h:59 [inline]
 get_current_ioprio include/linux/ioprio.h:83 [inline]
 init_sync_kiocb include/linux/fs.h:2345 [inline]
 __kernel_write_iter+0xe8/0x4e0 fs/read_write.c:614
 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:2903
 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

value changed: 0x0000000000000000 -> 0xffff88812d92dfe0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 14870 Comm: syz.0.4134 Tainted: G        W          6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/13 19:06 upstream f1b785f4c787 bb3f8425 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __kernel_write_iter / set_task_ioprio
2024/10/22 19:03 upstream d12937763990 a93682b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __kernel_write_iter / set_task_ioprio
* Struck through repros no longer work on HEAD.