loop4: detected capacity change from 0 to 264192 ================================================================== BUG: KCSAN: data-race in shmem_getattr / shmem_getpage_gfp write to 0xffff888104713a90 of 8 bytes by task 585 on cpu 1: shmem_getpage_gfp+0xf33/0x13d0 mm/shmem.c:1959 shmem_getpage mm/shmem.c:155 [inline] shmem_file_read_iter+0x1ae/0x5d0 mm/shmem.c:2571 call_read_iter include/linux/fs.h:2108 [inline] do_iter_readv_writev+0x2e8/0x360 fs/read_write.c:738 do_iter_read+0x109/0x4b0 fs/read_write.c:801 vfs_iter_read+0x4c/0x70 fs/read_write.c:843 lo_read_simple drivers/block/loop.c:404 [inline] do_req_filebacked drivers/block/loop.c:675 [inline] loop_handle_cmd drivers/block/loop.c:2204 [inline] loop_process_work+0x110b/0x1850 drivers/block/loop.c:2244 loop_rootcg_workfn+0x1b/0x20 drivers/block/loop.c:2275 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2276 worker_thread+0x636/0xae0 kernel/workqueue.c:2422 kthread+0x262/0x280 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 read to 0xffff888104713a90 of 8 bytes by task 21642 on cpu 0: shmem_getattr+0x41/0x250 mm/shmem.c:1043 vfs_getattr_nosec+0x152/0x2f0 fs/stat.c:105 vfs_getattr+0x4d/0x60 fs/stat.c:142 loop_get_status+0x23e/0x310 drivers/block/loop.c:1615 loop_get_status64 drivers/block/loop.c:1723 [inline] lo_ioctl+0x1b5/0x1340 drivers/block/loop.c:1868 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585 block_ioctl+0x6d/0x80 fs/block_dev.c:1604 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000000000000011 -> 0x0000000000000012 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 21642 Comm: syz-executor.4 Not tainted 5.14.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================