Hi, On Thu, Jul 18, 2019 at 05:18:07AM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: e40115c0 Add linux-next specific files for 20190717 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=11d51b70600000 > kernel config: https://syzkaller.appspot.com/x/.config?x=3430a151e1452331 > dashboard link: https://syzkaller.appspot.com/bug?extid=398343b7c1b1b989228d > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=164e7434600000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1399554c600000 > > The bug was bisected to: > > commit 71cbb7570a9a0b830125163c20125a8b5e65ac45 > Author: David Howells <dhowells@xxxxxxxxxx> > Date: Mon Mar 25 16:38:31 2019 +0000 > > vfs: Move the subtype parameter into fuse After this patch, if mount option is something like fd,XXXX (no "=" in XXXX), the default parameter which has NULL param->string is passed to vfs_parse_fs_param. And this NULL param->string is passed to kstrtouint and trigger null pointer access finally. Regards Yin, Fengwei > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14323078600000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=16323078600000 > console output: https://syzkaller.appspot.com/x/log.txt?x=12323078600000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+398343b7c1b1b989228d@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 71cbb7570a9a ("vfs: Move the subtype parameter into fuse") > > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 9017 Comm: syz-executor410 Not tainted 5.2.0-next-20190717 #40 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:kstrtoull lib/kstrtox.c:123 [inline] > RIP: 0010:kstrtouint+0x85/0x1a0 lib/kstrtox.c:222 > Code: 04 00 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 45 d0 31 c0 e8 6c 35 > 35 fe 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 4c 89 > e2 83 e2 07 38 d0 7f 08 84 c0 0f 85 db 00 00 00 > RSP: 0018:ffff8880997a79e0 EFLAGS: 00010246 > RAX: dffffc0000000000 RBX: ffff8880997a7b38 RCX: ffffffff81c482dc > RDX: 0000000000000000 RSI: ffffffff833d4f84 RDI: 0000000000000000 > RBP: ffff8880997a7a70 R08: ffff8880a17ce100 R09: ffffed1015d06c84 > R10: ffffed1015d06c83 R11: ffff8880ae83641b R12: 0000000000000000 > R13: 1ffff110132f4f3d R14: ffff8880997a7a48 R15: 0000000000000000 > FS: 0000555556585880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000455340 CR3: 0000000095a49000 CR4: 00000000001406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > fs_parse+0xde1/0x1080 fs/fs_parser.c:209 > fuse_parse_param+0xac/0x750 fs/fuse/inode.c:491 > vfs_parse_fs_param+0x2ca/0x540 fs/fs_context.c:145 > vfs_parse_fs_string+0x105/0x170 fs/fs_context.c:188 > generic_parse_monolithic+0x181/0x200 fs/fs_context.c:228 > parse_monolithic_mount_data+0x69/0x90 fs/fs_context.c:708 > do_new_mount fs/namespace.c:2779 [inline] > do_mount+0x1369/0x1c30 fs/namespace.c:3103 > ksys_mount+0xdb/0x150 fs/namespace.c:3312 > __do_sys_mount fs/namespace.c:3326 [inline] > __se_sys_mount fs/namespace.c:3323 [inline] > __x64_sys_mount+0xbe/0x150 fs/namespace.c:3323 > do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x440299 > Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff > 0f 83 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007fff19b997e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 > RAX: ffffffffffffffda RBX: 00007fff19b997f0 RCX: 0000000000440299 > RDX: 0000000020000080 RSI: 00000000200000c0 RDI: 0000000000000000 > RBP: 00000000006cb018 R08: 00000000200002c0 R09: 65732f636f72702f > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401b80 > R13: 0000000000401c10 R14: 0000000000000000 R15: 0000000000000000 > Modules linked in: > ---[ end trace 8c219e63b0160ea4 ]--- > RIP: 0010:kstrtoull lib/kstrtox.c:123 [inline] > RIP: 0010:kstrtouint+0x85/0x1a0 lib/kstrtox.c:222 > Code: 04 00 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 45 d0 31 c0 e8 6c 35 > 35 fe 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 4c 89 > e2 83 e2 07 38 d0 7f 08 84 c0 0f 85 db 00 00 00 > RSP: 0018:ffff8880997a79e0 EFLAGS: 00010246 > RAX: dffffc0000000000 RBX: ffff8880997a7b38 RCX: ffffffff81c482dc > RDX: 0000000000000000 RSI: ffffffff833d4f84 RDI: 0000000000000000 > RBP: ffff8880997a7a70 R08: ffff8880a17ce100 R09: ffffed1015d06c84 > R10: ffffed1015d06c83 R11: ffff8880ae83641b R12: 0000000000000000 > R13: 1ffff110132f4f3d R14: ffff8880997a7a48 R15: 0000000000000000 > FS: 0000555556585880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000455340 CR3: 0000000095a49000 CR4: 00000000001406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > --- > This bug 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 bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches
