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general protection fault in leaf_walk_rcu

Status: closed as invalid on 2025/07/30 09:20
Subsystems: net
[Documentation on labels]
First crash: 68d, last: 68d

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc001fffe000: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x00000000ffff0000-0x00000000ffff0007]
CPU: 0 UID: 0 PID: 9285 Comm: syz.3.973 Not tainted 6.16.0-rc2-next-20250617-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:leaf_walk_rcu+0x180/0x720 net/ipv4/fib_trie.c:1777
Code: f7 89 c3 31 ff 89 c6 e8 4e 86 c9 f7 85 db 74 3d e8 05 82 c9 f7 4d 85 e4 0f 84 2e 01 00 00 49 8d 5c 24 05 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 be 00 00 00 80 3b 00 0f 84 13 01 00 00
RSP: 0018:ffffc90002e27078 EFLAGS: 00010207
RAX: 000000001fffe000 RBX: 00000000ffff0005 RCX: 0000000000080000
RDX: ffffc9000ce5d000 RSI: 0000000000000ffe RDI: 0000000000000fff
RBP: 0000000000000000 R08: ffffc90002e27348 R09: 0000000000000000
R10: ffff8880797bb648 R11: ffffed100f2f76cd R12: 00000000ffff0000
R13: ffff8880283c7020 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f8ca778d6c0(0000) GS:ffff888125c40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555568e8e5c8 CR3: 0000000077692000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 fib_table_dump+0x217/0xe10 net/ipv4/fib_trie.c:2345
 inet_dump_fib+0x644/0x8e0 net/ipv4/fib_frontend.c:1074
 rtnl_dump_all+0x325/0x550 net/core/rtnetlink.c:4370
 rtnl_dumpit+0x9f/0x200 net/core/rtnetlink.c:6813
 netlink_dump+0x62d/0xe20 net/netlink/af_netlink.c:2309
 __netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2424
 netlink_dump_start include/linux/netlink.h:341 [inline]
 rtnetlink_dump_start net/core/rtnetlink.c:6842 [inline]
 rtnetlink_rcv_msg+0x9eb/0xb70 net/core/rtnetlink.c:6909
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x75b/0x8d0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 sock_write_iter+0x258/0x330 net/socket.c:1131
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x54b/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ca698e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8ca778d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8ca6bb6080 RCX: 00007f8ca698e929
RDX: 0000000000000032 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007f8ca6a10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f8ca6bb6080 R15: 00007ffe849904b8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:leaf_walk_rcu+0x180/0x720 net/ipv4/fib_trie.c:1777
Code: f7 89 c3 31 ff 89 c6 e8 4e 86 c9 f7 85 db 74 3d e8 05 82 c9 f7 4d 85 e4 0f 84 2e 01 00 00 49 8d 5c 24 05 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 be 00 00 00 80 3b 00 0f 84 13 01 00 00
RSP: 0018:ffffc90002e27078 EFLAGS: 00010207
RAX: 000000001fffe000 RBX: 00000000ffff0005 RCX: 0000000000080000
RDX: ffffc9000ce5d000 RSI: 0000000000000ffe RDI: 0000000000000fff
RBP: 0000000000000000 R08: ffffc90002e27348 R09: 0000000000000000
R10: ffff8880797bb648 R11: ffffed100f2f76cd R12: 00000000ffff0000
R13: ffff8880283c7020 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f8ca778d6c0(0000) GS:ffff888125c40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c29dadf CR3: 0000000077692000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	f7 89 c3 31 ff 89 c6 	testl  $0x864ee8c6,-0x7600ce3d(%rcx)
   7:	e8 4e 86
   a:	c9                   	leave
   b:	f7 85 db 74 3d e8 05 	testl  $0xf7c98205,-0x17c28b25(%rbp)
  12:	82 c9 f7
  15:	4d 85 e4             	test   %r12,%r12
  18:	0f 84 2e 01 00 00    	je     0x14c
  1e:	49 8d 5c 24 05       	lea    0x5(%r12),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 38       	movzbl (%rax,%r15,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 be 00 00 00    	jne    0xf5
  37:	80 3b 00             	cmpb   $0x0,(%rbx)
  3a:	0f 84 13 01 00 00    	je     0x153

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/17 14:21 linux-next 4325743c7e20 417d98fa .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in leaf_walk_rcu
* Struck through repros no longer work on HEAD.