syzbot

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BUG: KCSAN: data-race in block_uevent / inc_diskseq

write to 0xffff888102148618 of 8 bytes by task 3527 on cpu 1:
 inc_diskseq+0x2d/0x40 block/genhd.c:1583
 disk_force_media_change+0x9e/0xe0 block/disk-events.c:297
 __loop_clr_fd drivers/block/loop.c:1151 [inline]
 lo_release+0x2eb/0x420 drivers/block/loop.c:1751
 bdev_release+0x373/0x3d0 block/bdev.c:-1
 blkdev_release+0x15/0x20 block/fops.c:705
 __fput+0x29b/0x650 fs/file_table.c:469
 fput_close_sync+0xad/0x190 fs/file_table.c:574
 __do_sys_close fs/open.c:1509 [inline]
 __se_sys_close fs/open.c:1494 [inline]
 __x64_sys_close+0x55/0xf0 fs/open.c:1494
 x64_sys_call+0x275d/0x3020 arch/x86/include/generated/asm/syscalls_64.h:4
 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 0xffff888102148618 of 8 bytes by task 3000 on cpu 0:
 block_uevent+0x31/0x50 block/genhd.c:1320
 dev_uevent+0x375/0x400 drivers/base/core.c:2700
 uevent_show+0x11a/0x200 drivers/base/core.c:2756
 dev_attr_show+0x3f/0xa0 drivers/base/core.c:2421
 sysfs_kf_seq_show+0x1a3/0x280 fs/sysfs/file.c:65
 kernfs_seq_show+0x82/0xa0 fs/kernfs/file.c:223
 seq_read_iter+0x31e/0x940 fs/seq_file.c:231
 kernfs_fop_read_iter+0xc1/0x330 fs/kernfs/file.c:297
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x6c0/0x7f0 fs/read_write.c:574
 ksys_read+0xdc/0x1a0 fs/read_write.c:717
 __do_sys_read fs/read_write.c:726 [inline]
 __se_sys_read fs/read_write.c:724 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:724
 x64_sys_call+0x2886/0x3020 arch/x86/include/generated/asm/syscalls_64.h:1
 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

value changed: 0x000000000000002d -> 0x000000000000002e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3000 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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