syzbot


general protection fault in dccp_write_xmit

Status: upstream: reported C repro on 2023/12/12 16:47
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+2ff34c2e902e489b4d8c@syzkaller.appspotmail.com
First crash: 186d, last: 168d
Bug presence (2)
Date Name Commit Repro Result
2023/12/27 linux-6.1.y (ToT) 4aa6747d9352 C [report] BUG: unable to handle kernel paging request in corrupted
2023/12/27 upstream (ToT) fbafc3e621c3 C Didn't crash
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in dccp_write_xmit dccp C 5 2293d 2329d 4/27 fixed on 2018/03/23 18:14
upstream general protection fault in dccp_write_xmit (2) dccp C done 32 178d 234d 25/27 fixed on 2024/01/20 21:18
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2024/01/08 07:02 2h09m fix candidate upstream job log (0)

Sample crash report:
Unable to handle kernel paging request at virtual address dfff800000000000
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
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
[dfff800000000000] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 18236 Comm: syz-executor346 Not tainted 6.1.69-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ccid_hc_tx_send_packet net/dccp/ccid.h:166 [inline]
pc : dccp_write_xmit+0x6c/0x208 net/dccp/output.c:356
lr : dccp_write_xmit+0x30/0x208 net/dccp/output.c:355
sp : ffff8000250f74c0
x29: ffff8000250f74c0
 x28: ffff700004a1eeac
 x27: 00000000000f0000

x26: 1fffe0001b04eca6
 x25: dfff800000000000
 x24: 0000000000000000

x23: 0000000000000000 x22: ffff0000d3088dc0 x21: ffff800017fdf490
x20: ffff0000d8276530 x19: ffff0000d8275c40 x18: ffff8000250f7160
x17: ffff8000188a7000 x16: ffff8000084fa434 x15: ffff80001838cf80
x14: 0000000075644433
 x13: dfff800000000000
 x12: 0000000000000003
x11: 0000000000ff0100 x10: 0000000000000000 x9 : 1fffe0001b04ebd9
x8 : 0000000000000000
 x7 : 0000000000000000 x6 : 0000000000000000

x5 : ffff800018a21c28
 x4 : 0000000000000008 x3 : 0000000000000000

x2 : 0000000000000006
 x1 : 0000000000000000
 x0 : ffff0000d3088dc0
Call trace:
 ccid_hc_tx_send_packet net/dccp/ccid.h:166 [inline]
 dccp_write_xmit+0x6c/0x208 net/dccp/output.c:356
 dccp_sendmsg+0x634/0xb80 net/dccp/proto.c:798
 inet_sendmsg+0x15c/0x290 net/ipv4/af_inet.c:836
 sock_sendmsg_nosec net/socket.c:716 [inline]
 __sock_sendmsg net/socket.c:728 [inline]
 ____sys_sendmsg+0x558/0x844 net/socket.c:2499
 ___sys_sendmsg net/socket.c:2553 [inline]
 __sys_sendmmsg+0x318/0x7d8 net/socket.c:2639
 __do_sys_sendmmsg net/socket.c:2668 [inline]
 __se_sys_sendmmsg net/socket.c:2665 [inline]
 __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2665
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: aa1403e0 97a22f85 f9400297 d343fee8 (38796908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	aa1403e0 	mov	x0, x20
   4:	97a22f85 	bl	0xfffffffffe88be18
   8:	f9400297 	ldr	x23, [x20]
   c:	d343fee8 	lsr	x8, x23, #3
* 10:	38796908 	ldrb	w8, [x8, x25] <-- trapping instruction

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/12/27 00:28 linux-6.1.y 4aa6747d9352 fb427a07 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in dccp_write_xmit
2023/12/30 02:49 linux-6.1.y 4aa6747d9352 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in dccp_write_xmit
2023/12/12 16:46 linux-6.1.y e7cddbb41b63 ebcad15c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in dccp_write_xmit
2023/12/26 22:52 linux-6.1.y 4aa6747d9352 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in dccp_write_xmit
* Struck through repros no longer work on HEAD.