syzbot


BUG: unable to handle kernel NULL pointer dereference in exit_task_stack_account

Status: moderation: reported on 2022/11/28 22:17
Reported-by: syzbot+1d1c93741a8fb14abca8@syzkaller.appspotmail.com
First crash: 73d, last: 73d

Sample crash report:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
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
user pgtable: 4k pages, 48-bit VAs, pgdp=0000000151b74000
[0000000000000000] pgd=080000014d125003, p4d=080000014d125003, pud=0000000000000000
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 16876 Comm: syz-executor.1 Not tainted 6.1.0-rc6-syzkaller-32653-g65762d97e6fa #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : account_kernel_stack kernel/fork.c:495 [inline]
pc : exit_task_stack_account+0x2c/0x39c kernel/fork.c:508
lr : exit_task_stack_account+0x20/0x39c kernel/fork.c:507
sp : ffff80002249bc10
x29: ffff80002249bc10 x28: ffff0000c58acec0 x27: 0000000000000001
x26: ffff0000c58ad450 x25: ffff0000c58ad450 x24: ffff000108e99a40
x23: ffff80002249bc60 x22: ffff00010f8fb780 x21: ffff0000c58acec0
x20: 0000000000000000 x19: ffff0000c58acec0 x18: 00000000000000fe
x17: ffff80000c0cd83c x16: ffff80000dbe6158 x15: ffff0000c58acec0
x14: 0000000000000010 x13: 00000000ffffffff x12: ffff0000c58acec0
x11: ff808000080f0d8c x10: 0000000000000000 x9 : ffff8000080f0d8c
x8 : 0000000000000000 x7 : ffff8000085134c8 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 000000000000039c x1 : 0000000043736564 x0 : 0000000000000000
Call trace:
 account_kernel_stack kernel/fork.c:495 [inline]
 exit_task_stack_account+0x2c/0x39c kernel/fork.c:508
 do_exit+0x924/0xcac kernel/exit.c:862
 do_group_exit+0x98/0xcc kernel/exit.c:950
 get_signal+0xabc/0xb2c kernel/signal.c:2858
 do_signal+0x128/0x438 arch/arm64/kernel/signal.c:1071
 do_notify_resume+0xc0/0x1f0 arch/arm64/kernel/signal.c:1124
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 asm_exit_to_user_mode+0x70/0x84 arch/arm64/kernel/entry-common.c:149
 ret_from_fork+0x1c/0x20 arch/arm64/kernel/entry.S:866
Code: 9406d2f4 f94ace76 2a1f03e0 f94012c8 (f9400114) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	9406d2f4 	bl	0x1b4bd0
   4:	f94ace76 	ldr	x22, [x19, #5528]
   8:	2a1f03e0 	mov	w0, wzr
   c:	f94012c8 	ldr	x8, [x22, #32]
* 10:	f9400114 	ldr	x20, [x8] <-- trapping instruction

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-upstream-gce-arm64 2022/11/24 22:05 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 65762d97e6fa 62e26685 .config console log report info [disk image] [vmlinux] [kernel image] BUG: unable to handle kernel NULL pointer dereference in exit_task_stack_account
* Struck through repros no longer work on HEAD.