On Thu, Jun 07, 2018 at 08:28:46AM -0700, Matthew Wilcox wrote: > > I would suggest this is a BPF problem, not a VFS problem. > > On Thu, Jun 07, 2018 at 08:19:01AM -0700, syzbot wrote: > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: 7170e6045a6a strparser: Add __strp_unpause and use it in k.. > > git tree: net-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=14bde74f800000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=a601a80fec461d44 > > dashboard link: https://syzkaller.appspot.com/bug?extid=7ade6c94abb2774c0fee > > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+7ade6c94abb2774c0fee@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > bpfilter: read fail -512 > > kasan: GPF could be caused by NULL-ptr deref or user memory access > > general protection fault: 0000 [#1] SMP KASAN > > Dumping ftrace buffer: > > (ftrace buffer empty) > > Modules linked in: > > CPU: 1 PID: 4590 Comm: syz-executor7 Not tainted 4.17.0-rc7+ #82 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > RIP: 0010:file_write_hint include/linux/fs.h:1925 [inline] > > RIP: 0010:init_sync_kiocb include/linux/fs.h:1935 [inline] > > RIP: 0010:new_sync_write fs/read_write.c:470 [inline] > > RIP: 0010:__vfs_write+0x4a6/0x960 fs/read_write.c:487 > > RSP: 0018:ffff88019b5c7850 EFLAGS: 00010202 > > RAX: dffffc0000000000 RBX: ffff8801d2117c80 RCX: ffffffff81bfc6bb > > RDX: 0000000000000019 RSI: ffffffff81bfc6ca RDI: 00000000000000c8 > > RBP: ffff88019b5c79c8 R08: ffff88019b5ba540 R09: fffffbfff12cae69 > > R10: ffff88019b5c7a10 R11: ffffffff8965734b R12: 0000000000000000 > > R13: ffff88019b5c79a0 R14: 0000000000000000 R15: ffff88019b5c7a88 > > FS: 0000000002a11940(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000000000700138 CR3: 000000019b410000 CR4: 00000000001406e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > __kernel_write+0x10c/0x380 fs/read_write.c:506 > > __bpfilter_process_sockopt+0x1d8/0x35b net/bpfilter/bpfilter_kern.c:66 I think I see the problem. Will send the fix soon.
