[syzbot] KASAN: null-ptr-deref Write in alloc_buddy_huge_page

[syzbot] KASAN: null-ptr-deref Write in alloc_buddy_huge_page

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    aaa11ce2ffc8 Add linux-next specific files for 20220923
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16ea4288880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=186d1ff305f10294
dashboard link: https://syzkaller.appspot.com/bug?extid=db491b09f5907cdb5984
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=134606ef080000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16c83cff080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+db491b09f5907cdb5984@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
BUG: KASAN: null-ptr-deref in atomic_cmpxchg include/linux/atomic/atomic-instrumented.h:503 [inline]
BUG: KASAN: null-ptr-deref in page_ref_freeze include/linux/page_ref.h:318 [inline]
BUG: KASAN: null-ptr-deref in alloc_buddy_huge_page.isra.0+0x103/0x230 mm/hugetlb.c:1960
Write of size 4 at addr 0000000000000034 by task syz-executor107/3608

CPU: 0 PID: 3608 Comm: syz-executor107 Not tainted 6.0.0-rc6-next-20220923-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
 atomic_cmpxchg include/linux/atomic/atomic-instrumented.h:503 [inline]
 page_ref_freeze include/linux/page_ref.h:318 [inline]
 alloc_buddy_huge_page.isra.0+0x103/0x230 mm/hugetlb.c:1960
 alloc_fresh_huge_page+0x395/0x530 mm/hugetlb.c:2013
 alloc_surplus_huge_page+0x139/0x2f0 mm/hugetlb.c:2227
 alloc_buddy_huge_page_with_mpol mm/hugetlb.c:2304 [inline]
 alloc_huge_page+0xbf6/0x1180 mm/hugetlb.c:2919
 hugetlb_no_page mm/hugetlb.c:5571 [inline]
 hugetlb_fault+0x1056/0x1e60 mm/hugetlb.c:5796
 follow_hugetlb_page+0x3f3/0x1850 mm/hugetlb.c:6291
 __get_user_pages+0x2cb/0xf10 mm/gup.c:1146
 __get_user_pages_locked mm/gup.c:1378 [inline]
 __get_user_pages_remote+0x18f/0x830 mm/gup.c:2131
 pin_user_pages_remote+0x6c/0xb0 mm/gup.c:3189
 process_vm_rw_single_vec mm/process_vm_access.c:105 [inline]
 process_vm_rw_core.constprop.0+0x43b/0x980 mm/process_vm_access.c:215
 process_vm_rw+0x29c/0x300 mm/process_vm_access.c:283
 __do_sys_process_vm_writev mm/process_vm_access.c:303 [inline]
 __se_sys_process_vm_writev mm/process_vm_access.c:298 [inline]
 __x64_sys_process_vm_writev+0xdf/0x1b0 mm/process_vm_access.c:298
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7ff4166016c9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff99de70c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000137
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007ff4166016c9
RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000e18
RBP: 00007fff99de70e0 R08: 000000000000023a R09: 0000000000000000
R10: 0000000020121000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
==================================================================


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