syzbot

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BUG: KCSAN: data-race in touch_atime / touch_atime

write to 0xffff888101d883d8 of 4 bytes by task 19239 on cpu 0:
 inode_set_atime_to_ts include/linux/fs.h:1614 [inline]
 inode_update_timestamps fs/inode.c:2084 [inline]
 generic_update_time fs/inode.c:2106 [inline]
 inode_update_time fs/inode.c:2126 [inline]
 touch_atime+0x1f3/0x350 fs/inode.c:2198
 file_accessed include/linux/fs.h:2539 [inline]
 shmem_file_splice_read+0x561/0x5c0 mm/shmem.c:3406
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x398/0x660 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64 fs/read_write.c:1410 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
 x64_sys_call+0xfbd/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888101d883d8 of 4 bytes by task 19246 on cpu 1:
 inode_get_atime_nsec include/linux/fs.h:1599 [inline]
 inode_get_atime include/linux/fs.h:1605 [inline]
 inode_update_timestamps fs/inode.c:2081 [inline]
 generic_update_time fs/inode.c:2106 [inline]
 inode_update_time fs/inode.c:2126 [inline]
 touch_atime+0x1a0/0x350 fs/inode.c:2198
 file_accessed include/linux/fs.h:2539 [inline]
 shmem_file_splice_read+0x561/0x5c0 mm/shmem.c:3406
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x398/0x660 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64 fs/read_write.c:1410 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
 x64_sys_call+0xfbd/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x25c17946 -> 0x265a0fc6

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 19246 Comm: syz.6.6663 Tainted: G        W          6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
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BUG: KCSAN: data-race in shmem_file_splice_read / shmem_file_splice_read

write to 0xffff88811544e830 of 8 bytes by task 19239 on cpu 0:
 shmem_file_splice_read+0x438/0x5c0 mm/shmem.c:3396
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x398/0x660 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64 fs/read_write.c:1410 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
 x64_sys_call+0xfbd/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff88811544e830 of 8 bytes by task 19246 on cpu 1:
 shmem_file_splice_read+0x438/0x5c0 mm/shmem.c:3396
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x398/0x660 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64 fs/read_write.c:1410 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
 x64_sys_call+0xfbd/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000006ff4 -> 0x0000000000006ff5

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 19246 Comm: syz.6.6663 Tainted: G        W          6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
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