Re: kernel BUG at arch/x86/mm/physaddr.c:LINE!

[Dmitry Vyukov]

On Wed, Oct 10, 2018 at 5:22 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> On Wed, 10 Oct 2018, syzbot wrote:
>
> Cc+: Miklos

It seems reasonable to ignore arch/.*/mm/physaddr.c as suspected
guilty file in future -- we already ignore everything related to
kmalloc/kfree and this is called from kfree.
I've made the corresponding change to syzkaller:
https://github.com/google/syzkaller/commit/ba8cd6d708b97d6be4f9164758b6a7c690d252b2

Thanks for re-routing this one, Thomas!


>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit:    0854ba5ff5c9 Merge git://git.kernel.org/pub/scm/linux/kern..
>> git tree:       upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=15e64ea1400000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=88e9a8a39dc0be2d
>> dashboard link: https://syzkaller.appspot.com/bug?extid=ff03fe05c717b82502d0
>> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10e516a1400000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11d6e93a400000
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+ff03fe05c717b82502d0@xxxxxxxxxxxxxxxxxxxxxxxxx
>>
>> RBP: 00007ffc881226c0 R08: 0000000020000100 R09: 0000000000000100
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
>> R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000
>> overlayfs: failed to verify origin (syzkaller.Ry8w8Y/file0, ino=16483,
>> err=-12)
>> ------------[ cut here ]------------
>> kernel BUG at arch/x86/mm/physaddr.c:22!
>> invalid opcode: 0000 [#1] PREEMPT SMP KASAN
>> CPU: 0 PID: 5918 Comm: syz-executor189 Not tainted 4.19.0-rc7+ #53
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
>> 01/01/2011
>> RIP: 0010:__phys_addr+0xff/0x120 arch/x86/mm/physaddr.c:22
>> Code: 3c 02 00 75 31 4c 8b 25 ff c3 ee 07 48 89 de bf ff ff ff 1f e8 a2 7a 46
>> 00 49 01 dc 48 81 fb ff ff ff 1f 76 a7 e8 61 79 46 00 <0f> 0b e8 6a e9 89 00
>> e9 7a ff ff ff e8 c0 e9 89 00 eb c8 0f 1f 40
>> RSP: 0018:ffff8801c3387770 EFLAGS: 00010093
>> RAX: ffff8801c323a080 RBX: 000000007ffffff4 RCX: ffffffff81385c1e
>> RDX: 0000000000000000 RSI: ffffffff81385c2f RDI: 0000000000000007
>> RBP: ffff8801c3387788 R08: ffff8801c323a080 R09: ffffed003b5c4fe8
>> R10: ffffed003b5c4fe8 R11: ffff8801dae27f47 R12: 000000007ffffff4
>> R13: 0000000000000001 R14: ffffffff882f8c80 R15: 0000000000004063
>> FS:  000000000148d880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000000619570 CR3: 00000001c4ab0000 CR4: 00000000001406f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> virt_to_head_page include/linux/mm.h:658 [inline]
>> virt_to_cache mm/slab.c:399 [inline]
>> kfree+0x7b/0x230 mm/slab.c:3809
>> ovl_verify_set_fh+0xba/0x180 fs/overlayfs/namei.c:435
>> ovl_verify_origin fs/overlayfs/overlayfs.h:316 [inline]
>> ovl_get_indexdir fs/overlayfs/super.c:1139 [inline]
>> ovl_fill_super+0x3026/0x3f7b fs/overlayfs/super.c:1441
>> mount_nodev+0x6b/0x110 fs/super.c:1204
>> ovl_mount+0x2c/0x40 fs/overlayfs/super.c:1518
>> mount_fs+0xae/0x31d fs/super.c:1261
>> vfs_kern_mount.part.35+0xdc/0x4f0 fs/namespace.c:961
>> vfs_kern_mount fs/namespace.c:951 [inline]
>> do_new_mount fs/namespace.c:2457 [inline]
>> do_mount+0x581/0x31f0 fs/namespace.c:2787
>> ksys_mount+0x12d/0x140 fs/namespace.c:3003
>> __do_sys_mount fs/namespace.c:3017 [inline]
>> __se_sys_mount fs/namespace.c:3014 [inline]
>> __x64_sys_mount+0xbe/0x150 fs/namespace.c:3014
>> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>> RIP: 0033:0x4418e9
>> Code: 26 02 00 85 c0 b8 00 00 00 00 48 0f 44 c3 5b c3 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 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
>> RSP: 002b:00007ffc88122678 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
>> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004418e9
>> RDX: 00000000200000c0 RSI: 0000000020000000 RDI: 0000000000400000
>> RBP: 00007ffc881226c0 R08: 0000000020000100 R09: 0000000000000100
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
>> R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000
>> Modules linked in:
>> ---[ end trace 25e838f694c8a24f ]---
>> RIP: 0010:__phys_addr+0xff/0x120 arch/x86/mm/physaddr.c:22
>> Code: 3c 02 00 75 31 4c 8b 25 ff c3 ee 07 48 89 de bf ff ff ff 1f e8 a2 7a 46
>> 00 49 01 dc 48 81 fb ff ff ff 1f 76 a7 e8 61 79 46 00 <0f> 0b e8 6a e9 89 00
>> e9 7a ff ff ff e8 c0 e9 89 00 eb c8 0f 1f 40
>> RSP: 0018:ffff8801c3387770 EFLAGS: 00010093
>> RAX: ffff8801c323a080 RBX: 000000007ffffff4 RCX: ffffffff81385c1e
>> RDX: 0000000000000000 RSI: ffffffff81385c2f RDI: 0000000000000007
>> RBP: ffff8801c3387788 R08: ffff8801c323a080 R09: ffffed003b5c4fe8
>> R10: ffffed003b5c4fe8 R11: ffff8801dae27f47 R12: 000000007ffffff4
>> R13: 0000000000000001 R14: ffffffff882f8c80 R15: 0000000000004063
>> FS:  000000000148d880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000000619570 CR3: 00000001c4ab0000 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@xxxxxxxxxxxxxxxxx
>>
>> 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
>
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