Re: [syzbot] [net?] general protection fault in page_pool_unlist

From: Eric Dumazet
Date: Wed Nov 29 2023 - 06:16:11 EST


On Wed, Nov 29, 2023 at 12:06 PM syzbot
<syzbot+f9f8efb58a4db2ca98d0@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: a379972973a8 Merge branch 'net-page_pool-add-netlink-based..
> git tree: net-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1421b7ece80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=abf6d5a82dab01fe
> dashboard link: https://syzkaller.appspot.com/bug?extid=f9f8efb58a4db2ca98d0
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=117d9e64e80000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16826ec4e80000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/fc5f22d6faa1/disk-a3799729.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/e535e5c28162/vmlinux-a3799729.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/32eefbbcadbb/bzImage-a3799729.xz
>
> The issue was bisected to:
>
> commit 083772c9f972dcc248913b52a0dec1025baa1e16
> Author: Jakub Kicinski <kuba@xxxxxxxxxx>
> Date: Sun Nov 26 23:07:30 2023 +0000
>
> net: page_pool: record pools per netdev
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10c72162e80000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=12c72162e80000
> console output: https://syzkaller.appspot.com/x/log.txt?x=14c72162e80000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+f9f8efb58a4db2ca98d0@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: 083772c9f972 ("net: page_pool: record pools per netdev")
>
> Illegal XDP return value 4294946546 on prog (id 2) dev N/A, expect packet loss!
> general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 0 PID: 5064 Comm: syz-executor391 Not tainted 6.7.0-rc2-syzkaller-00533-ga379972973a8 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
> RIP: 0010:__hlist_del include/linux/list.h:988 [inline]
> RIP: 0010:hlist_del include/linux/list.h:1002 [inline]
> RIP: 0010:page_pool_unlist+0xd1/0x170 net/core/page_pool_user.c:342
> Code: df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 90 00 00 00 4c 8b a3 f0 06 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 68 48 85 ed 49 89 2c 24 74 24 e8 1b ca 07 f9 48 8d
> RSP: 0018:ffffc900039ff768 EFLAGS: 00010246
> RAX: dffffc0000000000 RBX: ffff88814ae02000 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88814ae026f0
> RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff1d57fdc
> R10: ffffffff8eabfee3 R11: ffffffff8aa0008b R12: 0000000000000000
> R13: ffff88814ae02000 R14: dffffc0000000000 R15: 0000000000000001
> FS: 000055555717a380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000002555398 CR3: 0000000025044000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> __page_pool_destroy net/core/page_pool.c:851 [inline]
> page_pool_release+0x507/0x6b0 net/core/page_pool.c:891
> page_pool_destroy+0x1ac/0x4c0 net/core/page_pool.c:956
> xdp_test_run_teardown net/bpf/test_run.c:216 [inline]
> bpf_test_run_xdp_live+0x1578/0x1af0 net/bpf/test_run.c:388
> bpf_prog_test_run_xdp+0x827/0x1530 net/bpf/test_run.c:1254
> bpf_prog_test_run kernel/bpf/syscall.c:4041 [inline]
> __sys_bpf+0x11bf/0x4920 kernel/bpf/syscall.c:5402
> __do_sys_bpf kernel/bpf/syscall.c:5488 [inline]
> __se_sys_bpf kernel/bpf/syscall.c:5486 [inline]
> __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5486
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
> RIP: 0033:0x7f616195a4a9
> Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffe858ce5c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> RAX: ffffffffffffffda RBX: 00007ffe858ce798 RCX: 00007f616195a4a9
> RDX: 0000000000000048 RSI: 0000000020000340 RDI: 000000000000000a
> RBP: 00007f61619cd610 R08: 0000000000000000 R09: 00007ffe858ce798
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> R13: 00007ffe858ce788 R14: 0000000000000001 R15: 0000000000000001
> </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:__hlist_del include/linux/list.h:988 [inline]
> RIP: 0010:hlist_del include/linux/list.h:1002 [inline]
> RIP: 0010:page_pool_unlist+0xd1/0x170 net/core/page_pool_user.c:342
> Code: df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 90 00 00 00 4c 8b a3 f0 06 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 68 48 85 ed 49 89 2c 24 74 24 e8 1b ca 07 f9 48 8d
> RSP: 0018:ffffc900039ff768 EFLAGS: 00010246
> RAX: dffffc0000000000 RBX: ffff88814ae02000 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88814ae026f0
> RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff1d57fdc
> R10: ffffffff8eabfee3 R11: ffffffff8aa0008b R12: 0000000000000000
> R13: ffff88814ae02000 R14: dffffc0000000000 R15: 0000000000000001
> FS: 000055555717a380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f2640df1b10 CR3: 0000000025044000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> ----------------
> Code disassembly (best guess):
> 0: df 48 89 fisttps -0x77(%rax)
> 3: fa cli
> 4: 48 c1 ea 03 shr $0x3,%rdx
> 8: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
> c: 0f 85 90 00 00 00 jne 0xa2
> 12: 4c 8b a3 f0 06 00 00 mov 0x6f0(%rbx),%r12
> 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
> 20: fc ff df
> 23: 4c 89 e2 mov %r12,%rdx
> 26: 48 c1 ea 03 shr $0x3,%rdx
> * 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
> 2e: 75 68 jne 0x98
> 30: 48 85 ed test %rbp,%rbp
> 33: 49 89 2c 24 mov %rbp,(%r12)
> 37: 74 24 je 0x5d
> 39: e8 1b ca 07 f9 call 0xf907ca59
> 3e: 48 rex.W
> 3f: 8d .byte 0x8d
>
>
> ---
> This report 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 issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup


#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
main

```
diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
index 1426434a7e1587797da92f3199c0012559b51271..07becd4eceddcd4be9e5bea6479f8ffd16dac851
100644
--- a/net/core/page_pool_user.c
+++ b/net/core/page_pool_user.c
@@ -339,7 +339,8 @@ void page_pool_unlist(struct page_pool *pool)
mutex_lock(&page_pools_lock);
netdev_nl_page_pool_event(pool, NETDEV_CMD_PAGE_POOL_DEL_NTF);
xa_erase(&page_pools, pool->user.id);
- hlist_del(&pool->user.list);
+ if (!hlist_unhashed(&pool->user.list))
+ hlist_del(&pool->user.list);
mutex_unlock(&page_pools_lock);
}

```