================================================================== BUG: KCSAN: data-race in filemap_map_pages / shmem_write_end read to 0xffff8880b7fffcf0 of 8 bytes by task 30277 on cpu 0: filemap_map_pages+0x812/0x990 mm/filemap.c:2663 do_fault_around mm/memory.c:3450 [inline] do_read_fault mm/memory.c:3484 [inline] do_fault mm/memory.c:3618 [inline] handle_pte_fault mm/memory.c:3849 [inline] __handle_mm_fault+0x2554/0x2cb0 mm/memory.c:3973 handle_mm_fault+0x21b/0x530 mm/memory.c:4010 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline] __do_page_fault+0x3fb/0x9e0 arch/x86/mm/fault.c:1506 do_page_fault+0x54/0x233 arch/x86/mm/fault.c:1530 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1202 do_strncpy_from_user lib/strncpy_from_user.c:47 [inline] strncpy_from_user+0x177/0x2b0 lib/strncpy_from_user.c:120 getname_flags fs/namei.c:149 [inline] getname_flags+0xc3/0x380 fs/namei.c:128 getname+0x23/0x40 fs/namei.c:209 do_sys_open+0x27f/0x4f0 fs/open.c:1091 ksys_open include/linux/syscalls.h:1385 [inline] __do_sys_creat fs/open.c:1155 [inline] __se_sys_creat fs/open.c:1153 [inline] __x64_sys_creat+0x45/0x60 fs/open.c:1153 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 write to 0xffff8880b7fffcf0 of 8 bytes by task 30281 on cpu 1: i_size_write include/linux/fs.h:888 [inline] shmem_write_end+0x83/0x4f0 mm/shmem.c:2493 generic_perform_write+0x1d3/0x320 mm/filemap.c:3315 __generic_file_write_iter+0x251/0x380 mm/filemap.c:3433 generic_file_write_iter+0x28c/0x390 mm/filemap.c:3465 call_write_iter include/linux/fs.h:1895 [inline] do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693 do_iter_write fs/read_write.c:970 [inline] do_iter_write+0x13b/0x3c0 fs/read_write.c:951 vfs_iter_write+0x5c/0x80 fs/read_write.c:983 iter_file_splice_write+0x4c0/0x7f0 fs/splice.c:746 do_splice_from fs/splice.c:848 [inline] direct_splice_actor+0xa0/0xc0 fs/splice.c:1020 splice_direct_to_actor+0x215/0x510 fs/splice.c:975 do_splice_direct+0x161/0x1e0 fs/splice.c:1063 do_sendfile+0x384/0x7f0 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1519 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0xbe/0x140 fs/read_write.c:1511 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 30281 Comm: syz-executor.4 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================