[syzbot] [arm?] BUG: unable to handle kernel paging request in huge_pte_alloc

Sat Apr 13 19:59:27 PDT 2024

Hello,

syzbot found the following issue on:

HEAD commit:    2c71fdf02a95 Merge tag 'drm-fixes-2024-04-09' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16b397ad180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3b59c588989b5f9a
dashboard link: https://syzkaller.appspot.com/bug?extid=8b093786303cd0c2041d
compiler:       aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16f55d29180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15a32e75180000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/384ffdcca292/non_bootable_disk-2c71fdf0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/627c4a5b3fcb/vmlinux-2c71fdf0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/39628cd13511/Image-2c71fdf0.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8b093786303cd0c2041d at syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address ffffffffc0000000
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, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
swapper pgtable: 4k pages, 52-bit VAs, pgdp=00000000425f4000
[ffffffffc0000000] pgd=1000000042ac9003, p4d=00000000429e0003, pud=00000000429e1003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 3176 Comm: syz-executor300 Not tainted 6.9.0-rc3-syzkaller-00023-g2c71fdf02a95 #0
Hardware name: linux,dummy-virt (DT)
pstate: 01400009 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : pud_alloc include/linux/mm.h:2819 [inline]
pc : huge_pte_alloc+0xd4/0x358 arch/arm64/mm/hugetlbpage.c:280
lr : copy_hugetlb_page_range+0x108/0x924 mm/hugetlb.c:5423
sp : ffff8000890e3810
x29: ffff8000890e3810 x28: ffff80008283c358 x27: fcf0000005e14980
x26: 0000000000000000 x25: fbf0000005e15300 x24: f8f0000006360780
x23: f8f0000006360780 x22: fcf0000005e14980 x21: 0000000021000000
x20: 0000000020400000 x19: ffffffffc0000000 x18: ffff8000890e3ba8
x17: 0000000000000000 x16: 1ede000000c4c181 x15: 0000000000000001
x14: ffffffffffffffff x13: 0000000000000000 x12: ffff8000890e3ac8
x11: 0000000020400000 x10: ffff8000890e3ba8 x9 : 0000000020400000
x8 : 0000000000000000 x7 : 0000000000000102 x6 : 0000000040000000
x5 : 0000000000000000 x4 : ffffffffc0000000 x3 : 0000000000200000
x2 : f3f0000005f34f80 x1 : 0000000000000000 x0 : 0000000040000000
Call trace:
 p4d_offset_lockless arch/arm64/include/asm/pgtable.h:965 [inline]
 p4d_offset arch/arm64/include/asm/pgtable.h:971 [inline]
 huge_pte_alloc+0xd4/0x358 arch/arm64/mm/hugetlbpage.c:279
 copy_hugetlb_page_range+0x108/0x924 mm/hugetlb.c:5423
 copy_page_range+0x1a0c/0x1a58 mm/memory.c:1355
 dup_mmap kernel/fork.c:747 [inline]
 dup_mm kernel/fork.c:1687 [inline]
 copy_mm+0x62c/0x7ac kernel/fork.c:1736
 copy_process+0xc30/0x1484 kernel/fork.c:2389
 kernel_clone+0x64/0x360 kernel/fork.c:2796
 __do_sys_clone+0x70/0xa8 kernel/fork.c:2939
 __se_sys_clone kernel/fork.c:2907 [inline]
 __arm64_sys_clone+0x20/0x2c kernel/fork.c:2907
 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
 invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:48
 el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:133
 do_el0_svc+0x1c/0x28 arch/arm64/kernel/syscall.c:152
 el0_svc+0x34/0xf8 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:598
Code: aa010084 cb000084 b24c2c84 8b130c93 (f9400260) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	aa010084 	orr	x4, x4, x1
   4:	cb000084 	sub	x4, x4, x0
   8:	b24c2c84 	orr	x4, x4, #0xfff0000000000000
   c:	8b130c93 	add	x19, x4, x19, lsl #3
* 10:	f9400260 	ldr	x0, [x19] <-- trapping instruction

---
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