BUG: unable to handle kernel paging request in sctp_outq_tail

Status: fixed on 2023/05/11 04:30
Fix commit: 667eb99cf7c1 sctp: check send stream number after wait_for_sndbuf
First crash: 208d, last: 177d
Fix bisection: fixed by (bisect log) :
commit 667eb99cf7c15fe5b0ecefe75cf658e20ef20c9f
Author: Xin Long <>
Date: Sat Apr 1 23:09:57 2023 +0000

  sctp: check send stream number after wait_for_sndbuf

Bug presence (1)
Date Name Commit Repro Result
2023/05/04 upstream (ToT) 1a5304fecee5 C Didn't crash
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 BUG: unable to handle kernel paging request in sctp_outq_tail origin:lts-only C done 2 102d 207d 3/3 fixed on 2023/08/21 17:07
upstream general protection fault in sctp_outq_tail sctp C error 5 182d 194d 24/25 fixed on 2023/06/08 14:41
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2023/05/10 21:27 7h00m bisect fix linux-5.15.y job log (1)
2023/04/09 06:53 46m bisect fix linux-5.15.y job log (0) log

Sample crash report:
Unable to handle kernel paging request at virtual address dfff800000000007
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006
  CM = 0, WnR = 0
[dfff800000000007] address between user and kernel address ranges
Internal error: Oops: 96000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 6011 Comm: syz-executor243 Not tainted 5.15.98-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : list_add_tail include/linux/list.h:100 [inline]
pc : sctp_outq_tail_data net/sctp/outqueue.c:91 [inline]
pc : sctp_outq_tail+0x270/0xa1c net/sctp/outqueue.c:299
lr : sctp_stream_out include/net/sctp/structs.h:1493 [inline]
lr : sctp_outq_tail_data net/sctp/outqueue.c:90 [inline]
lr : sctp_outq_tail+0x244/0xa1c net/sctp/outqueue.c:299
sp : ffff800020527290
x29: ffff8000205272a0 x28: 0000000000000007 x27: dfff800000000000
x26: 0000000000000038 x25: 0000000000000030 x24: ffff0000e3212b90
x23: ffff0000e3212b58 x22: ffff0000e3212ba0 x21: ffff0000e3212b40
x20: ffff0000e0c987f0 x19: 1fffe0001c642574 x18: 0000000000000000
x17: ff808000110536ac x16: ffff8000084c28f4 x15: ffff8000110536ac
x14: 0000000000000040 x13: ffffffffffffffff x12: 0000000000000000
x11: ff8080000a9a25b8 x10: 0000000000000000 x9 : ffff80000a9a25b8
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 000000000000003f
x5 : ffff800020527420 x4 : ffff0000e0ad1400 x3 : ffff800011010344
x2 : ffff0000e0c987f8 x1 : 00000000000000c0 x0 : ffff0000e314b0c0
Call trace:
 list_add_tail include/linux/list.h:100 [inline]
 sctp_outq_tail_data net/sctp/outqueue.c:91 [inline]
 sctp_outq_tail+0x270/0xa1c net/sctp/outqueue.c:299
 sctp_cmd_send_msg net/sctp/sm_sideeffect.c:1114 [inline]
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1777 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
 sctp_do_sm+0x2858/0x4dc4 net/sctp/sm_sideeffect.c:1170
 sctp_primitive_SEND+0x98/0xc8 net/sctp/primitive.c:163
 sctp_sendmsg_to_asoc+0x1058/0x17dc net/sctp/socket.c:1869
 sctp_sendmsg+0x196c/0x2844 net/sctp/socket.c:2027
 inet_sendmsg+0x15c/0x290 net/ipv4/af_inet.c:823
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 __sys_sendto+0x388/0x4d0 net/socket.c:2039
 __do_sys_sendto net/socket.c:2051 [inline]
 __se_sys_sendto net/socket.c:2047 [inline]
 __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2047
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 <unknown>:584
Code: 910062b7 9100e11a 9100c119 d343ff5c (387b6b89) 
---[ end trace b6c276d6bae36334 ]---
Code disassembly (best guess):
   0:	910062b7 	add	x23, x21, #0x18
   4:	9100e11a 	add	x26, x8, #0x38
   8:	9100c119 	add	x25, x8, #0x30
   c:	d343ff5c 	lsr	x28, x26, #3
* 10:	387b6b89 	ldrb	w9, [x28, x27] <-- trapping instruction

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/03/08 23:48 linux-5.15.y d9b4a0c83a2d 4fc6d98d .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: unable to handle kernel paging request in sctp_outq_tail
2023/03/10 06:52 linux-5.15.y d9b4a0c83a2d f08b59ac .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in sctp_outq_tail
* Struck through repros no longer work on HEAD.