On Wed, Aug 29, 2018 at 3:46 PM Jan Kara <jack@xxxxxxx> wrote: > > On Tue 28-08-18 08:30:02, syzbot wrote: > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: 5b394b2ddf03 Linux 4.19-rc1 > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=14f4d8e1400000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=49927b422dcf0b29 > > dashboard link: https://syzkaller.appspot.com/bug?extid=45a34334c61a8ecf661d > > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13127e5a400000 > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+45a34334c61a8ecf661d@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready > > IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready > > IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready > > 8021q: adding VLAN 0 to HW filter on device team0 > > ================================================================== > > BUG: KASAN: stack-out-of-bounds in schedule_debug kernel/sched/core.c:3285 > > [inline] > > BUG: KASAN: stack-out-of-bounds in __schedule+0x1977/0x1df0 > > kernel/sched/core.c:3395 > > Read of size 8 at addr ffff8801ad090000 by task syz-executor0/4718 > > Weird, can you please help me decipher this? So here KASAN complains about > wrong memory access in the scheduler. Most certainly the following code: #ifdef CONFIG_SCHED_STACK_END_CHECK if (task_stack_end_corrupted(prev)) panic("corrupted stack end detected inside scheduler\n"); #endif in schedule_debug() triggers the KASAN report. I guess we must disable CONFIG_SCHED_STACK_END_CHECK for KASAN builds. > However the stacktrace below shows a > problem in find_stack() function called by KASAN? For some reason the stackdepot hash table is corrupted. Looks like a separate issue. > And this does not seem to > be fs related at all? Also the reproducer has no sign of any filesystem > related activity... > > Honza > > > CPU: 0 PID: 4718 Comm: syz-executor0 Not tainted 4.19.0-rc1+ #211 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > Call Trace: > > > > The buggy address belongs to the page: > > page:ffffea0006b42400 count:1 mapcount:-512 mapping:0000000000000000 > > index:0x0 > > flags: 0x2fffc0000000000() > > raw: 02fffc0000000000 dead000000000100 dead000000000200 0000000000000000 > > raw: 0000000000000000 0000000000000000 00000001fffffdff ffff8801d29544c0 > > page dumped because: kasan: bad access detected > > page->mem_cgroup:ffff8801d29544c0 > > > > Memory state around the buggy address: > > ffff8801ad08ff00: f2 f2 f2 f2 f2 00 f2 f2 f2 00 00 00 00 00 00 00 > > ffff8801ad08ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 > > > ffff8801ad090000: f1 f1 f1 00 f2 f2 f2 f2 f2 f2 f2 04 f2 f2 f2 f2 > > ^ > > ffff8801ad090080: f2 f2 f2 00 f2 f2 f2 00 00 00 00 00 00 00 00 00 > > ffff8801ad090100: 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 > > ================================================================== > > Kernel panic - not syncing: panic_on_warn set ... > > > > BUG: unable to handle kernel paging request at 0000000100000007 > > PGD 1b34a2067 P4D 1b34a2067 PUD 0 > > Oops: 0000 [#1] SMP KASAN > > CPU: 1 PID: 4325 Comm: rs:main Q:Reg Tainted: G B 4.19.0-rc1+ > > #211 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > RIP: 0010:find_stack lib/stackdepot.c:188 [inline] > > RIP: 0010:depot_save_stack+0x120/0x470 lib/stackdepot.c:238 > > Code: 0f 00 4e 8b 24 f5 e0 db ae 89 4d 85 e4 0f 84 d4 00 00 00 44 8d 47 ff > > 49 c1 e0 03 eb 0d 4d 8b 24 24 4d 85 e4 0f 84 bd 00 00 00 <41> 39 5c 24 08 75 > > ec 41 3b 7c 24 0c 75 e5 48 8b 01 49 39 44 24 18 > > RSP: 0018:ffff8801b2636f40 EFLAGS: 00010006 > > RAX: 0000000084727a0d RBX: 00000000222ca320 RCX: ffff8801b2636fa0 > > RDX: 000000004e510a9d RSI: 0000000000400000 RDI: 0000000000000012 > > RBP: ffff8801b2636f78 R08: 0000000000000088 R09: 00000000dcf06c78 > > R10: 00000000ecfd654a R11: ffff8801db1236f3 R12: 00000000ffffffff > > R13: ffff8801b2636f88 R14: 00000000000ca320 R15: ffff8801b2a72680 > > FS: 00007ff2eb061700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000000100000007 CR3: 00000001b4fdd000 CR4: 00000000001406e0 > > Call Trace: > > save_stack+0xa9/0xd0 mm/kasan/kasan.c:454 > > set_track mm/kasan/kasan.c:460 [inline] > > __kasan_slab_free+0x11a/0x170 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+0x86/0x280 mm/slab.c:3756 > > jbd2_free_handle include/linux/jbd2.h:1426 [inline] > > jbd2_journal_stop+0x443/0x1600 fs/jbd2/transaction.c:1787 > > __ext4_journal_stop+0xde/0x1f0 fs/ext4/ext4_jbd2.c:103 > > ext4_dirty_inode+0xab/0xc0 fs/ext4/inode.c:6027 > > __mark_inode_dirty+0x760/0x1300 fs/fs-writeback.c:2129 > > generic_update_time+0x26a/0x450 fs/inode.c:1651 > > update_time fs/inode.c:1667 [inline] > > file_update_time+0x390/0x640 fs/inode.c:1877 > > __generic_file_write_iter+0x1dc/0x630 mm/filemap.c:3214 > > ext4_file_write_iter+0x390/0x1450 fs/ext4/file.c:266 > > call_write_iter include/linux/fs.h:1807 [inline] > > new_sync_write fs/read_write.c:474 [inline] > > __vfs_write+0x6af/0x9d0 fs/read_write.c:487 > > vfs_write+0x1fc/0x560 fs/read_write.c:549 > > ksys_write+0x101/0x260 fs/read_write.c:598 > > __do_sys_write fs/read_write.c:610 [inline] > > __se_sys_write fs/read_write.c:607 [inline] > > __x64_sys_write+0x73/0xb0 fs/read_write.c:607 > > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > RIP: 0033:0x7ff2ecabf19d > > Code: d1 20 00 00 75 10 b8 01 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 > > 83 ec 08 e8 be fa ff ff 48 89 04 24 b8 01 00 00 00 0f 05 <48> 8b 3c 24 48 89 > > c2 e8 07 fb ff ff 48 89 d0 48 83 c4 08 48 3d 01 > > RSP: 002b:00007ff2eb05ff90 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 > > RAX: ffffffffffffffda RBX: 0000000000000400 RCX: 00007ff2ecabf19d > > RDX: 0000000000000400 RSI: 0000000002089a90 RDI: 0000000000000005 > > RBP: 0000000002089a90 R08: 00000000020d9e00 R09: 656c6c616b7a7973 > > R10: 6c656e72656b2072 R11: 0000000000000293 R12: 0000000000000000 > > R13: 00007ff2eb060410 R14: 00000000020d9e00 R15: 0000000002089890 > > Modules linked in: > > Dumping ftrace buffer: > > (ftrace buffer empty) > > CR2: 0000000100000007 > > ---[ end trace fbf1ba842de6c894 ]--- > > RIP: 0010:find_stack lib/stackdepot.c:188 [inline] > > RIP: 0010:depot_save_stack+0x120/0x470 lib/stackdepot.c:238 > > Code: 0f 00 4e 8b 24 f5 e0 db ae 89 4d 85 e4 0f 84 d4 00 00 00 44 8d 47 ff > > 49 c1 e0 03 eb 0d 4d 8b 24 24 4d 85 e4 0f 84 bd 00 00 00 <41> 39 5c 24 08 75 > > ec 41 3b 7c 24 0c 75 e5 48 8b 01 49 39 44 24 18 > > RSP: 0018:ffff8801b2636f40 EFLAGS: 00010006 > > RAX: 0000000084727a0d RBX: 00000000222ca320 RCX: ffff8801b2636fa0 > > RDX: 000000004e510a9d RSI: 0000000000400000 RDI: 0000000000000012 > > RBP: ffff8801b2636f78 R08: 0000000000000088 R09: 00000000dcf06c78 > > R10: 00000000ecfd654a R11: ffff8801db1236f3 R12: 00000000ffffffff > > R13: ffff8801b2636f88 R14: 00000000000ca320 R15: ffff8801b2a72680 > > FS: 00007ff2eb061700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000000100000007 CR3: 00000001b4fdd000 CR4: 00000000001406e0 > > Shutting down cpus with NMI > > Dumping ftrace buffer: > > (ftrace buffer empty) > > Kernel Offset: disabled > > Rebooting in 86400 seconds.. > > > > > > --- > > 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. > > syzbot can test patches for this bug, for details see: > > https://goo.gl/tpsmEJ#testing-patches > > > -- > Jan Kara <jack@xxxxxxxx> > SUSE Labs, CR > > -- > 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/20180829134620.GD7369%40quack2.suse.cz. > For more options, visit https://groups.google.com/d/optout. -- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg
