syzbot

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BUG: KCSAN: data-race in __kernel_write_iter / set_task_ioprio

write to 0xffff888128173b38 of 8 bytes by task 14738 on cpu 1:
 set_task_ioprio+0x24e/0x270 block/blk-ioc.c:280
 __do_sys_ioprio_set block/ioprio.c:121 [inline]
 __se_sys_ioprio_set+0x24f/0x5a0 block/ioprio.c:65
 __x64_sys_ioprio_set+0x43/0x50 block/ioprio.c:65
 x64_sys_call+0x2bbf/0x3020 arch/x86/include/generated/asm/syscalls_64.h:252
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888128173b38 of 8 bytes by task 14733 on cpu 0:
 __get_task_ioprio include/linux/ioprio.h:59 [inline]
 get_current_ioprio include/linux/ioprio.h:84 [inline]
 init_sync_kiocb include/linux/fs.h:2194 [inline]
 __kernel_write_iter+0xdb/0x590 fs/read_write.c:619
 dump_emit_page fs/coredump.c:1299 [inline]
 dump_user_range+0xa7d/0xdb0 fs/coredump.c:1373
 elf_core_dump+0x21a2/0x2330 fs/binfmt_elf.c:2110
 coredump_write+0xacc/0xdd0 fs/coredump.c:1050
 do_coredump fs/coredump.c:1127 [inline]
 vfs_coredump+0x26c7/0x3130 fs/coredump.c:1201
 get_signal+0xd80/0xf60 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:64 [inline]
 exit_to_user_mode_loop+0x6a/0x6f0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x249/0x370 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff88810162fc80

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 14733 Comm: syz.3.1966 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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