syzbot


general protection fault in __skb_frag_ref

Status: internal: reported on 2024/12/23 01:43
Subsystems: net
[Documentation on labels]
Fix commit: cbb26f7d8451 mptcp: fix TCP options overflow.
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-qemu2-arm32 ci-qemu2-riscv64 ci-upstream-bpf-next-kasan-gce]
First crash: 22d, last: 11d

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 UID: 0 PID: 22748 Comm: syz-executor Not tainted 6.13.0-rc5-syzkaller-00012-g0bc21e701a6f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:_compound_head include/linux/page-flags.h:242 [inline]
RIP: 0010:get_page include/linux/mm.h:1461 [inline]
RIP: 0010:__skb_frag_ref+0x4d/0x1d0 include/linux/skbuff_ref.h:20
Code: 48 89 df e8 a5 be 7c f8 4c 8b 33 31 c0 4c 89 f6 48 83 e6 01 4c 0f 45 f0 31 ff e8 7e e6 18 f8 49 8d 5e 08 48 89 d8 48 c1 e8 03 <80> 3c 28 00 74 08 48 89 df e8 75 be 7c f8 48 8b 1b 48 89 de 48 83
RSP: 0018:ffffc90000a18840 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: ffff88807e668000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff898691f2 R09: 1ffff1100c9dfa6c
R10: dffffc0000000000 R11: ffffed100c9dfa6d R12: dffffc0000000000
R13: ffff888064efd370 R14: 0000000000000000 R15: 0000000000000000
FS:  0000555556f20500(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 000000009ae16000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 skb_frag_ref include/linux/skbuff_ref.h:32 [inline]
 pskb_expand_head+0x74b/0x1380 net/core/skbuff.c:2300
 __skb_unclone_keeptruesize+0x87/0x2c0 net/core/skbuff.c:2375
 skb_unclone_keeptruesize include/linux/skbuff.h:1998 [inline]
 __tcp_retransmit_skb+0x58d/0x1500 net/ipv4/tcp_output.c:3376
 tcp_send_loss_probe+0x426/0x8f0 net/ipv4/tcp_output.c:2982
 tcp_write_timer+0x166/0x2e0 net/ipv4/tcp_timer.c:735
 call_timer_fn+0x187/0x650 kernel/time/timer.c:1793
 expire_timers kernel/time/timer.c:1844 [inline]
 __run_timers kernel/time/timer.c:2418 [inline]
 __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430
 run_timer_base kernel/time/timer.c:2439 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 4a 48 b7 f5 48 89 df e8 82 8f b8 f5 e8 6d a0 e3 f5 fb bf 01 00 00 00 <e8> a2 f4 a9 f5 65 8b 05 13 47 40 74 85 c0 74 06 5b c3 cc cc cc cc
RSP: 0018:ffffc9000d0476b8 EFLAGS: 00000286
RAX: cfd153d75cbaf000 RBX: ffff888059fabe70 RCX: ffffffff817b26fa
RDX: dffffc0000000000 RSI: ffffffff8c0a98e0 RDI: 0000000000000001
RBP: dffffc0000000000 R08: ffffffff94271897 R09: 1ffffffff284e312
R10: dffffc0000000000 R11: fffffbfff284e313 R12: 0000000000000019
R13: 1ffff1100b3f57cd R14: ffffea00010b8b40 R15: ffff888059fabe68
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 filemap_remove_folio+0xe9/0x1f0 mm/filemap.c:265
 truncate_inode_folio+0x5d/0x70 mm/truncate.c:162
 shmem_undo_range+0x44b/0x1820 mm/shmem.c:1040
 shmem_truncate_range mm/shmem.c:1156 [inline]
 shmem_evict_inode+0x29b/0xa80 mm/shmem.c:1284
 evict+0x4e8/0x9a0 fs/inode.c:796
 do_unlinkat+0x512/0x830 fs/namei.c:4594
 __do_sys_unlink fs/namei.c:4635 [inline]
 __se_sys_unlink fs/namei.c:4633 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:4633
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f98eab852d7
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 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:00007fff3706c708 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f98eab852d7
RDX: 00007fff3706c730 RSI: 00007fff3706c7c0 RDI: 00007fff3706c7c0
RBP: 00007fff3706c7c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007fff3706d840
R13: 00007f98eac018f4 R14: 00007fff3706d880 R15: 0000000000000122
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:_compound_head include/linux/page-flags.h:242 [inline]
RIP: 0010:get_page include/linux/mm.h:1461 [inline]
RIP: 0010:__skb_frag_ref+0x4d/0x1d0 include/linux/skbuff_ref.h:20
Code: 48 89 df e8 a5 be 7c f8 4c 8b 33 31 c0 4c 89 f6 48 83 e6 01 4c 0f 45 f0 31 ff e8 7e e6 18 f8 49 8d 5e 08 48 89 d8 48 c1 e8 03 <80> 3c 28 00 74 08 48 89 df e8 75 be 7c f8 48 8b 1b 48 89 de 48 83
RSP: 0018:ffffc90000a18840 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: ffff88807e668000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff898691f2 R09: 1ffff1100c9dfa6c
R10: dffffc0000000000 R11: ffffed100c9dfa6d R12: dffffc0000000000
R13: ffff888064efd370 R14: 0000000000000000 R15: 0000000000000000
FS:  0000555556f20500(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 000000009ae16000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 89 df             	mov    %rbx,%rdi
   3:	e8 a5 be 7c f8       	call   0xf87cbead
   8:	4c 8b 33             	mov    (%rbx),%r14
   b:	31 c0                	xor    %eax,%eax
   d:	4c 89 f6             	mov    %r14,%rsi
  10:	48 83 e6 01          	and    $0x1,%rsi
  14:	4c 0f 45 f0          	cmovne %rax,%r14
  18:	31 ff                	xor    %edi,%edi
  1a:	e8 7e e6 18 f8       	call   0xf818e69d
  1f:	49 8d 5e 08          	lea    0x8(%r14),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 75 be 7c f8       	call   0xf87cbead
  38:	48 8b 1b             	mov    (%rbx),%rbx
  3b:	48 89 de             	mov    %rbx,%rsi
  3e:	48                   	rex.W
  3f:	83                   	.byte 0x83

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/02 23:26 upstream 0bc21e701a6f d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root general protection fault in __skb_frag_ref
2024/12/23 01:42 upstream bcde95ce32b6 b4fbdbd4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in __skb_frag_ref
* Struck through repros no longer work on HEAD.