================================================================== BUG: KCSAN: data-race in block_uevent / inc_diskseq write to 0xffff8881021a6620 of 8 bytes by task 3315 on cpu 0: inc_diskseq+0x2d/0x40 block/genhd.c:1517 disk_force_media_change+0x9e/0xe0 block/disk-events.c:297 __loop_clr_fd drivers/block/loop.c:1139 [inline] lo_release+0x2cb/0x400 drivers/block/loop.c:1719 bdev_release+0x370/0x3d0 block/bdev.c:-1 blkdev_release+0x15/0x20 block/fops.c:660 __fput+0x298/0x650 fs/file_table.c:465 fput_close_sync+0x6e/0x120 fs/file_table.c:570 __do_sys_close fs/open.c:1581 [inline] __se_sys_close fs/open.c:1566 [inline] __x64_sys_close+0x56/0xf0 fs/open.c:1566 x64_sys_call+0x2747/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:4 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff8881021a6620 of 8 bytes by task 3004 on cpu 1: block_uevent+0x31/0x50 block/genhd.c:1256 dev_uevent+0x349/0x3d0 drivers/base/core.c:2703 uevent_show+0x117/0x200 drivers/base/core.c:2759 dev_attr_show+0x3c/0xa0 drivers/base/core.c:2424 sysfs_kf_seq_show+0x1a0/0x280 fs/sysfs/file.c:65 kernfs_seq_show+0x7f/0xa0 fs/kernfs/file.c:205 seq_read_iter+0x316/0x940 fs/seq_file.c:230 kernfs_fop_read_iter+0xc4/0x300 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x5ca/0x6f0 fs/read_write.c:570 ksys_read+0xda/0x1a0 fs/read_write.c:713 __do_sys_read fs/read_write.c:722 [inline] __se_sys_read fs/read_write.c:720 [inline] __x64_sys_read+0x40/0x50 fs/read_write.c:720 x64_sys_call+0x2d77/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:1 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000000000b4 -> 0x00000000000000b7 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 3004 Comm: udevd Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 ==================================================================