================================================================== BUG: KCSAN: data-race in shmem_add_to_page_cache / shmem_recalc_inode write to 0xffff88811fa72558 of 8 bytes by task 11054 on cpu 0: shmem_add_to_page_cache+0x4b0/0x6c0 mm/shmem.c:643 shmem_getpage_gfp+0x43f/0x16c0 mm/shmem.c:1871 shmem_fault+0x117/0x4b0 mm/shmem.c:2062 __do_fault+0xa8/0x1e0 mm/memory.c:3450 do_read_fault mm/memory.c:3846 [inline] do_fault mm/memory.c:3975 [inline] handle_pte_fault mm/memory.c:4215 [inline] __handle_mm_fault+0x295c/0x2da0 mm/memory.c:4345 handle_mm_fault+0x21c/0x540 mm/memory.c:4382 faultin_page mm/gup.c:879 [inline] __get_user_pages+0x533/0x11c0 mm/gup.c:1098 populate_vma_page_range+0xdc/0x100 mm/gup.c:1430 __mm_populate+0x168/0x2b0 mm/gup.c:1478 mm_populate include/linux/mm.h:2562 [inline] vm_mmap_pgoff+0x185/0x190 mm/util.c:511 ksys_mmap_pgoff+0x96/0x420 mm/mmap.c:1595 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff88811fa72558 of 8 bytes by task 11018 on cpu 1: shmem_recalc_inode+0x50/0x180 mm/shmem.c:306 shmem_getpage_gfp+0x5ca/0x16c0 mm/shmem.c:1885 shmem_fault+0x117/0x4b0 mm/shmem.c:2062 __do_fault+0xa8/0x1e0 mm/memory.c:3450 do_read_fault mm/memory.c:3846 [inline] do_fault mm/memory.c:3975 [inline] handle_pte_fault mm/memory.c:4215 [inline] __handle_mm_fault+0x295c/0x2da0 mm/memory.c:4345 handle_mm_fault+0x21c/0x540 mm/memory.c:4382 do_user_addr_fault arch/x86/mm/fault.c:1464 [inline] do_page_fault+0x48a/0xa96 arch/x86/mm/fault.c:1535 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203 fault_in_pages_readable include/linux/pagemap.h:601 [inline] iov_iter_fault_in_readable+0x22b/0x2c0 lib/iov_iter.c:431 generic_perform_write+0xc6/0x320 mm/filemap.c:3292 ext4_buffered_write_iter+0x14e/0x280 fs/ext4/file.c:270 ext4_file_write_iter+0xf4/0xd30 fs/ext4/file.c:642 call_write_iter include/linux/fs.h:1907 [inline] new_sync_write+0x303/0x400 fs/read_write.c:484 __vfs_write+0x9e/0xb0 fs/read_write.c:497 vfs_write fs/read_write.c:559 [inline] vfs_write+0x189/0x380 fs/read_write.c:543 ksys_write+0xc5/0x1a0 fs/read_write.c:612 __do_sys_write fs/read_write.c:624 [inline] __se_sys_write fs/read_write.c:621 [inline] __x64_sys_write+0x49/0x60 fs/read_write.c:621 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 11018 Comm: syz-executor.3 Not tainted 5.7.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================