[moderation] [fs?] [mm?] KCSAN: data-race in ondemand_readahead / read_pages (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2c8159388952 Merge tag 'rust-fixes-6.9' of https://github...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=153fd327180000
kernel config: https://syzkaller.appspot.com/x/.config?x=566553eb991172d
dashboard link: https://syzkaller.appspot.com/bug?extid=f12141c8cf8742e5060e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@kvack.org wi...@infradead.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2ad1a82f7176/disk-2c815938.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1381fe67ae94/vmlinux-2c815938.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3b6cce54d183/bzImage-2c815938.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f12141...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in ondemand_readahead / read_pages

read-write to 0xffff88811529f880 of 4 bytes by task 18266 on cpu 0:
read_pages+0x23f/0x540 mm/readahead.c:170
page_cache_ra_unbounded+0x225/0x2e0
do_page_cache_ra mm/readahead.c:299 [inline]
page_cache_ra_order mm/readahead.c:539 [inline]
ondemand_readahead+0x549/0x6c0 mm/readahead.c:661
page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:688
page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
filemap_splice_read+0x360/0x920 mm/filemap.c:2870
ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x26c/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+0x3b9/0x970 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
x64_sys_call+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff88811529f880 of 4 bytes by task 18271 on cpu 1:
ondemand_readahead+0x2e2/0x6c0 mm/readahead.c:639
page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:688
page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
filemap_splice_read+0x360/0x920 mm/filemap.c:2870
ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x26c/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+0x3b9/0x970 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
x64_sys_call+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000d -> 0x00000010

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18271 Comm: syz-executor.4 Not tainted 6.9.0-rc5-syzkaller-00355-g2c8159388952 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================
==================================================================
BUG: KCSAN: data-race in read_pages / read_pages

read-write to 0xffff88811529f880 of 4 bytes by task 18266 on cpu 1:
read_pages+0x23f/0x540 mm/readahead.c:170
page_cache_ra_unbounded+0x225/0x2e0
do_page_cache_ra mm/readahead.c:299 [inline]
page_cache_ra_order mm/readahead.c:539 [inline]
ondemand_readahead+0x549/0x6c0 mm/readahead.c:661
page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:688
page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
filemap_splice_read+0x360/0x920 mm/filemap.c:2870
ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x26c/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+0x3b9/0x970 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
x64_sys_call+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read-write to 0xffff88811529f880 of 4 bytes by task 18271 on cpu 0:
read_pages+0x23f/0x540 mm/readahead.c:170
page_cache_ra_unbounded+0x2a4/0x2e0 mm/readahead.c:269
do_page_cache_ra mm/readahead.c:299 [inline]
page_cache_ra_order mm/readahead.c:539 [inline]
ondemand_readahead+0x549/0x6c0 mm/readahead.c:661
page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:688
page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
filemap_splice_read+0x360/0x920 mm/filemap.c:2870
ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x26c/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+0x3b9/0x970 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
x64_sys_call+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000a -> 0xffffffef

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18271 Comm: syz-executor.4 Not tainted 6.9.0-rc5-syzkaller-00355-g2c8159388952 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================


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