loop5: detected capacity change from 0 to 127 ================================================================== BUG: KCSAN: data-race in shmem_add_to_page_cache / shmem_getattr write to 0xffff888137106770 of 8 bytes by task 7436 on cpu 1: shmem_add_to_page_cache+0x52d/0x650 mm/shmem.c:718 shmem_getpage_gfp+0xb8f/0x13d0 mm/shmem.c:1951 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:363 [inline] do_req_filebacked drivers/block/loop.c:634 [inline] loop_handle_cmd drivers/block/loop.c:2138 [inline] loop_process_work+0x110b/0x1850 drivers/block/loop.c:2178 loop_rootcg_workfn+0x1b/0x20 drivers/block/loop.c:2209 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 0xffff888137106770 of 8 bytes by task 12321 on cpu 0: shmem_getattr+0x6e/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:1549 loop_get_status64 drivers/block/loop.c:1657 [inline] lo_ioctl+0x1b0/0x1210 drivers/block/loop.c:1802 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585 block_ioctl+0x6d/0x80 fs/block_dev.c:1602 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: 0x0000000000000001 -> 0x0000000000000002 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 12321 Comm: syz-executor.5 Not tainted 5.14.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ================================================================== loop5: detected capacity change from 0 to 127