[moderation] [mm?] KCSAN: data-race in shmem_fallocate / shmem_fault (7)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9bacdd8996c7 Merge tag 'for-6.7-rc1-tag' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13397a2f680000
kernel config: https://syzkaller.appspot.com/x/.config?x=a91f789b98394377
dashboard link: https://syzkaller.appspot.com/bug?extid=2cb26506a9fe7a5fec94
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org hu...@google.com linux-...@vger.kernel.org linu...@kvack.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/be70757ec048/disk-9bacdd89.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/45e8c725b4dc/vmlinux-9bacdd89.xz
kernel image: https://storage.googleapis.com/syzbot-assets/82e551f976a9/bzImage-9bacdd89.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2cb265...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in shmem_fallocate / shmem_fault

write to 0xffff888142195480 of 8 bytes by task 5822 on cpu 0:
shmem_fallocate+0x32f/0x860 mm/shmem.c:3080
vfs_fallocate+0x378/0x3e0 fs/open.c:324
madvise_remove mm/madvise.c:990 [inline]
madvise_vma_behavior mm/madvise.c:1014 [inline]
madvise_walk_vmas mm/madvise.c:1249 [inline]
do_madvise+0x741/0x26f0 mm/madvise.c:1429
__do_sys_madvise mm/madvise.c:1442 [inline]
__se_sys_madvise mm/madvise.c:1440 [inline]
__x64_sys_madvise+0x60/0x70 mm/madvise.c:1440
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888142195480 of 8 bytes by task 5821 on cpu 1:
shmem_fault+0x9d/0x250 mm/shmem.c:2206
__do_fault mm/memory.c:4265 [inline]
do_read_fault mm/memory.c:4628 [inline]
do_fault mm/memory.c:4762 [inline]
do_pte_missing mm/memory.c:3730 [inline]
handle_pte_fault mm/memory.c:5038 [inline]
__handle_mm_fault mm/memory.c:5179 [inline]
handle_mm_fault+0x13bd/0x2dd0 mm/memory.c:5344
faultin_page mm/gup.c:956 [inline]
__get_user_pages+0x402/0xe40 mm/gup.c:1239
populate_vma_page_range mm/gup.c:1677 [inline]
__mm_populate+0x216/0x330 mm/gup.c:1786
mm_populate include/linux/mm.h:3379 [inline]
vm_mmap_pgoff+0x1a7/0x240 mm/util.c:551
ksys_mmap_pgoff+0xc5/0x330 mm/mmap.c:1425
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xffffc9000d653cd0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5821 Comm: syz-executor.2 Not tainted 6.7.0-rc1-syzkaller-00012-g9bacdd8996c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.