On Mon 24-04-23 10:27:46, Dmitry Vyukov wrote: > On Mon, 24 Apr 2023 at 10:09, syzbot > <syzbot+4a06d4373fd52f0b2f9c@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 622322f53c6d Merge tag 'mips-fixes_6.3_2' of git://git.ker.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=1482ffafc80000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=fa4baf7c6b35b5d5 > > dashboard link: https://syzkaller.appspot.com/bug?extid=4a06d4373fd52f0b2f9c > > 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/8b5f31d96315/disk-622322f5.raw.xz > > vmlinux: https://storage.googleapis.com/syzbot-assets/adca7dc8daae/vmlinux-622322f5.xz > > kernel image: https://storage.googleapis.com/syzbot-assets/ed78ddc31ccb/bzImage-622322f5.xz > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+4a06d4373fd52f0b2f9c@xxxxxxxxxxxxxxxxxxxxxxxxx > > If I am reading this correctly, userspace can get wd=-1 as the result > of this race. Docs say wd must refer to a previously allocated > descriptor, which is positive. I don't see any mentions of semantics > of wd=-1. Yeah, indeed this looks like a possible race when we detach the mark just while we are generating the event. I'll send a fix. Honza > > ================================================================== > > BUG: KCSAN: data-race in inotify_handle_inode_event / inotify_remove_from_idr > > > > write to 0xffff888104e31368 of 4 bytes by task 3229 on cpu 1: > > inotify_remove_from_idr+0x106/0x310 fs/notify/inotify/inotify_user.c:511 > > inotify_ignored_and_remove_idr+0x34/0x60 fs/notify/inotify/inotify_user.c:532 > > inotify_freeing_mark+0x1d/0x30 fs/notify/inotify/inotify_fsnotify.c:133 > > fsnotify_free_mark fs/notify/mark.c:490 [inline] > > fsnotify_destroy_mark+0x17a/0x190 fs/notify/mark.c:499 > > __do_sys_inotify_rm_watch fs/notify/inotify/inotify_user.c:817 [inline] > > __se_sys_inotify_rm_watch+0xf7/0x170 fs/notify/inotify/inotify_user.c:794 > > __x64_sys_inotify_rm_watch+0x31/0x40 fs/notify/inotify/inotify_user.c:794 > > 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 0xffff888104e31368 of 4 bytes by task 3638 on cpu 0: > > inotify_handle_inode_event+0x17e/0x2c0 fs/notify/inotify/inotify_fsnotify.c:113 > > fsnotify_handle_inode_event+0x19b/0x1f0 fs/notify/fsnotify.c:264 > > fsnotify_handle_event fs/notify/fsnotify.c:316 [inline] > > send_to_group fs/notify/fsnotify.c:364 [inline] > > fsnotify+0x101c/0x1150 fs/notify/fsnotify.c:570 > > __fsnotify_parent+0x307/0x480 fs/notify/fsnotify.c:230 > > fsnotify_parent include/linux/fsnotify.h:77 [inline] > > fsnotify_file include/linux/fsnotify.h:99 [inline] > > fsnotify_close include/linux/fsnotify.h:341 [inline] > > __fput+0x4b0/0x570 fs/file_table.c:307 > > ____fput+0x15/0x20 fs/file_table.c:349 > > task_work_run+0x123/0x160 kernel/task_work.c:179 > > resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] > > exit_to_user_mode_loop+0xd1/0xe0 kernel/entry/common.c:171 > > exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204 > > __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] > > syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297 > > do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 > > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > > > value changed: 0x00000060 -> 0xffffffff > > > > Reported by Kernel Concurrency Sanitizer on: > > CPU: 0 PID: 3638 Comm: syz-executor.0 Not tainted 6.3.0-rc7-syzkaller-00191-g622322f53c6d #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 > > ================================================================== > > > > > > --- > > 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/000000000000c2e89505fa108749%40google.com. -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
