On Mon, 24 Apr 2023 at 10:10, syzbot <syzbot+f682b67a78ce05867e78@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: cb0856346a60 Merge tag 'mm-hotfixes-stable-2023-04-19-16-3.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=10b9e8bfc80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=fa4baf7c6b35b5d5 > dashboard link: https://syzkaller.appspot.com/bug?extid=f682b67a78ce05867e78 > compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/a02dd7789fb2/disk-cb085634.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/a1a1eac454f6/vmlinux-cb085634.xz > kernel image: https://storage.googleapis.com/syzbot-assets/bb0447014913/bzImage-cb085634.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+f682b67a78ce05867e78@xxxxxxxxxxxxxxxxxxxxxxxxx I think shmem_unlink() needs to use i_size_write() to update the size. Writes to i_size are not assumed to be atomic throughout the kernel code. > ================================================================== > BUG: KCSAN: data-race in generic_fillattr / shmem_unlink > > read-write to 0xffff888104d167b8 of 8 bytes by task 23887 on cpu 1: > shmem_unlink+0x102/0x190 mm/shmem.c:3036 > vfs_unlink+0x261/0x3e0 fs/namei.c:4250 > do_unlinkat+0x266/0x4f0 fs/namei.c:4316 > __do_sys_unlink fs/namei.c:4364 [inline] > __se_sys_unlink fs/namei.c:4362 [inline] > __x64_sys_unlink+0x30/0x40 fs/namei.c:4362 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > read to 0xffff888104d167b8 of 8 bytes by task 27823 on cpu 0: > i_size_read include/linux/fs.h:866 [inline] > generic_fillattr+0x13f/0x1e0 fs/stat.c:58 > shmem_getattr+0x32a/0x3b0 mm/shmem.c:1068 > vfs_getattr_nosec+0x1e3/0x3c0 fs/stat.c:133 > vfs_getattr fs/stat.c:170 [inline] > vfs_statx+0x156/0x300 fs/stat.c:242 > vfs_fstatat fs/stat.c:276 [inline] > __do_sys_newfstatat fs/stat.c:446 [inline] > __se_sys_newfstatat+0x8a/0x2a0 fs/stat.c:440 > __x64_sys_newfstatat+0x55/0x60 fs/stat.c:440 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > value changed: 0x00000000000000c8 -> 0x00000000000000b4 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 0 PID: 27823 Comm: udevd Not tainted 6.3.0-rc7-syzkaller-00089-gcb0856346a60 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/0000000000001db82205fa108b35%40google.com.
