KCSAN: data-race in __kernel_write_iter / set_task

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __kernel_write_iter / set_task_ioprio (2) block	6				1	214d	214d	0/29	auto-obsoleted due to no activity on 2025/07/26 03:33
upstream	KCSAN: data-race in __kernel_write_iter / set_task_ioprio block	6				7	294d	434d	0/29	auto-obsoleted due to no activity on 2025/05/06 16:02

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BUG: KCSAN: data-race in __kernel_write_iter / set_task_ioprio

write to 0xffff88811b6e65cc of 2 bytes by task 20200 on cpu 0:
 set_task_ioprio+0x117/0x270 block/blk-ioc.c:282
 __do_sys_ioprio_set block/ioprio.c:121 [inline]
 __se_sys_ioprio_set+0x250/0x5a0 block/ioprio.c:65
 __x64_sys_ioprio_set+0x43/0x50 block/ioprio.c:65
 x64_sys_call+0x2781/0x3000 arch/x86/include/generated/asm/syscalls_64.h:252
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811b6e65cc of 2 bytes by task 20181 on cpu 1:
 __get_task_ioprio include/linux/ioprio.h:69 [inline]
 get_current_ioprio include/linux/ioprio.h:84 [inline]
 init_sync_kiocb include/linux/fs.h:2177 [inline]
 __kernel_write_iter+0xf7/0x540 fs/read_write.c:617
 dump_emit_page fs/coredump.c:1298 [inline]
 dump_user_range+0x61e/0x8f0 fs/coredump.c:1372
 elf_core_dump+0x1de7/0x1f80 fs/binfmt_elf.c:2111
 coredump_write+0xacf/0xdf0 fs/coredump.c:1049
 do_coredump fs/coredump.c:1126 [inline]
 vfs_coredump+0x24f7/0x2e60 fs/coredump.c:1200
 get_signal+0xd84/0xf70 kernel/signal.c:3019
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:75 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0xfb/0x560 kernel/entry/common.c:196
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

value changed: 0x4007 -> 0x0000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 20181 Comm: syz.7.2823 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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