On Tue, Nov 6, 2018 at 9:03 PM, syzbot <syzbot+34a98afb89842107f03f@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: d881de30d29e Add linux-next specific files for 20181107 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=16e42f5b400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=caa433e1c8778437 > dashboard link: https://syzkaller.appspot.com/bug?extid=34a98afb89842107f03f > 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+34a98afb89842107f03f@xxxxxxxxxxxxxxxxxxxxxxxxx This is another manifestation of the following report, right? #syz dup: KASAN: use-after-free Read in locks_delete_block > ================================================================== > BUG: KASAN: use-after-free in locks_remove_flock+0x33c/0x350 fs/locks.c:2567 > Read of size 8 at addr ffff8801c92fc040 by task syz-executor1/15515 > > CPU: 1 PID: 15515 Comm: syz-executor1 Not tainted 4.20.0-rc1-next-20181107+ > #107 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x244/0x39d lib/dump_stack.c:113 > print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 > locks_remove_flock+0x33c/0x350 fs/locks.c:2567 > locks_remove_file+0x148/0x5c0 fs/locks.c:2607 > __fput+0x2f0/0xa70 fs/file_table.c:271 > ____fput+0x15/0x20 fs/file_table.c:312 > task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 > tracehook_notify_resume include/linux/tracehook.h:188 [inline] > exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 > prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] > syscall_return_slowpath arch/x86/entry/common.c:268 [inline] > do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x457569 > Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007fc1e8ed4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000049 > RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000457569 > RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000003 > RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc1e8ed56d4 > R13: 00000000004bdd9e R14: 00000000004ccdb8 R15: 00000000ffffffff > > Allocated by task 15515: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 > kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 > kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554 > kmem_cache_zalloc include/linux/slab.h:731 [inline] > locks_alloc_lock+0x9e/0x300 fs/locks.c:304 > flock_make_lock+0x22c/0x2a0 fs/locks.c:438 > __do_sys_flock fs/locks.c:2057 [inline] > __se_sys_flock fs/locks.c:2038 [inline] > __x64_sys_flock+0x12b/0x350 fs/locks.c:2038 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 15515: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kmem_cache_free+0x83/0x290 mm/slab.c:3760 > locks_free_lock+0x295/0x420 fs/locks.c:341 > __do_sys_flock fs/locks.c:2078 [inline] > __se_sys_flock fs/locks.c:2038 [inline] > __x64_sys_flock+0x289/0x350 fs/locks.c:2038 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8801c92fc000 > which belongs to the cache file_lock_cache of size 264 > The buggy address is located 64 bytes inside of > 264-byte region [ffff8801c92fc000, ffff8801c92fc108) > The buggy address belongs to the page: > page:ffffea000724bf00 count:1 mapcount:0 mapping:ffff8801d9a1c3c0 index:0x0 > flags: 0x2fffc0000000200(slab) > raw: 02fffc0000000200 ffff8801d9a82e48 ffffea00075e1608 ffff8801d9a1c3c0 > raw: 0000000000000000 ffff8801c92fc000 000000010000000c 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801c92fbf00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc > ffff8801c92fbf80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >> >> ffff8801c92fc000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ^ > ffff8801c92fc080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801c92fc100: fb fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb > ================================================================== > ------------[ cut here ]------------ > downgrading a read lock > WARNING: CPU: 0 PID: 15521 at kernel/locking/lockdep.c:3556 __lock_downgrade > kernel/locking/lockdep.c:3556 [inline] > WARNING: CPU: 0 PID: 15521 at kernel/locking/lockdep.c:3556 > lock_downgrade+0x4d7/0x900 kernel/locking/lockdep.c:3819 > > > --- > 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#bug-status-tracking 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/0000000000008628be057a0c089f%40google.com. > For more options, visit https://groups.google.com/d/optout.
