syzbot


BUG: unable to handle kernel paging request in smk_fetch

Status: moderation: reported on 2022/09/20 00:19
Reported-by: syzbot+f94365823dae3ef742c1@syzkaller.appspotmail.com
First crash: 74d, last: 74d

Sample crash report:
Unable to handle kernel paging request at virtual address dead4ead00000080
Mem abort info:
  ESR = 0x0000000096000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x04: level 0 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000004
  CM = 0, WnR = 0
[dead4ead00000080] address between user and kernel address ranges
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:

CPU: 1 PID: 3257 Comm: syz-executor.3 Not tainted 6.0.0-rc4-syzkaller-17255-ga6b443748715 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : slab_alloc mm/slub.c:3251 [inline]
pc : kmem_cache_alloc_trace+0x184/0x340 mm/slub.c:3282
lr : slab_pre_alloc_hook mm/slab.h:702 [inline]
lr : slab_alloc_node mm/slub.c:3157 [inline]
lr : slab_alloc mm/slub.c:3251 [inline]
lr : kmem_cache_alloc_trace+0x8c/0x340 mm/slub.c:3282
sp : ffff800020483ac0
x29: ffff800020483ad0
 x28: ffff000105129a80
 x27: ffff80000d339000

x26: ffff80000cba4535
 x25: ffff80000d5fb5a0 x24: dead4ead00000000
x23: 0000000000000000 x22: ffff80000942c6ac x21: ffff0000c0001300
x20: 0000000000000100 x19: 0000000000000d40 x18: 0000000000000000
x17: 0000000000000000 x16: ffff80000db78658 x15: ffff000105129a80
x14: 0000000000000010 x13: 0000000000000000 x12: ffff000105129a80
x11: 0000000000000001 x10: 0000000000000000 x9 : 0000000000000080
x8 : 0000000000594ef9 x7 : ffff8000084b2d80 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000594f01
x2 : 0000000000000000 x1 : 0000000000000100 x0 : 0000000000000000
Call trace:
 next_tid mm/slub.c:2311 [inline]
 slab_alloc_node mm/slub.c:3227 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 kmem_cache_alloc_trace+0x184/0x340 mm/slub.c:3282
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 smk_fetch+0x58/0xf4 security/smack/smack_lsm.c:291
 smack_d_instantiate+0x2c8/0x480 security/smack/smack_lsm.c:3410
 security_d_instantiate+0x74/0xa4 security/security.c:2056
 d_instantiate_new+0x40/0xc8 fs/dcache.c:2053
 ext4_add_nondir+0x11c/0x140 fs/ext4/namei.c:2764
 ext4_symlink+0x410/0x514 fs/ext4/namei.c:3394
 vfs_symlink+0x170/0x218 fs/namei.c:4378
 do_symlinkat+0xcc/0x2bc fs/namei.c:4407
 __do_sys_symlinkat fs/namei.c:4424 [inline]
 __se_sys_symlinkat fs/namei.c:4421 [inline]
 __arm64_sys_symlinkat+0x58/0x70 fs/namei.c:4421
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
 el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:624
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:642
 el0t_64_sync+0x18c/0x190
Code: 54000e21 34000e2b b9402aa9 91002103 (f8696b19) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	54000e21 	b.ne	0x1c4  // b.any
   4:	34000e2b 	cbz	w11, 0x1c8
   8:	b9402aa9 	ldr	w9, [x21, #40]
   c:	91002103 	add	x3, x8, #0x8
* 10:	f8696b19 	ldr	x25, [x24, x9] <-- trapping instruction

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-gce-arm64 2022/09/16 00:11 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a6b443748715 dd9a85ff .config log report info BUG: unable to handle kernel paging request in smk_fetch
* Struck through repros no longer work on HEAD.