Re: [syzbot] [mm?] WARNING in try_grab_page

From: syzbot
Date: Tue Sep 05 2023 - 13:55:43 EST


syzbot has found a reproducer for the following issue on:

HEAD commit: 3f86ed6ec0b3 Merge tag 'arc-6.6-rc1' of git://git.kernel.o..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=139ce690680000
kernel config: https://syzkaller.appspot.com/x/.config?x=ff0db7a15ba54ead
dashboard link: https://syzkaller.appspot.com/bug?extid=9b82859567f2e50c123e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10b0c620680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=152da4e7a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6f4f710c5033/disk-3f86ed6e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/555548fedbdc/vmlinux-3f86ed6e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c06d7c39bbc0/bzImage-3f86ed6e.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/120cc7b707b8/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9b82859567f2e50c123e@xxxxxxxxxxxxxxxxxxxxxxxxx

XFS (loop0): Quotacheck needed: Please wait.
XFS (loop0): Quotacheck: Done.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5030 at mm/gup.c:229 try_grab_page+0x287/0x460
Modules linked in:
CPU: 1 PID: 5030 Comm: syz-executor118 Not tainted 6.5.0-syzkaller-11704-g3f86ed6ec0b3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:try_grab_page+0x287/0x460 mm/gup.c:229
Code: 01 49 8d 7e 60 be 04 00 00 00 e8 54 41 18 00 f0 41 83 46 60 01 42 80 3c 2b 00 0f 85 6a ff ff ff e9 6d ff ff ff e8 b9 55 be ff <0f> 0b bb f4 ff ff ff eb b6 e8 ab 55 be ff 49 ff ce e9 ca fd ff ff
RSP: 0018:ffffc90003a6ee88 EFLAGS: 00010293
RAX: ffffffff81cf4377 RBX: 0000000000000000 RCX: ffff888025da0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 000000000000000e R08: ffffffff81cf418c R09: 1ffffd400039097e
R10: dffffc0000000000 R11: fffff9400039097f R12: ffffea0001c84bf4
R13: dffffc0000000000 R14: ffffea0001c84bc0 R15: ffffea0001c84bc0
FS: 0000555555acb380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020008000 CR3: 00000000736e9000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
follow_page_pte+0x560/0x18f0 mm/gup.c:651
follow_pud_mask mm/gup.c:765 [inline]
follow_p4d_mask mm/gup.c:782 [inline]
follow_page_mask+0x7dc/0xe20 mm/gup.c:832
__get_user_pages+0x643/0x15e0 mm/gup.c:1237
__get_user_pages_locked mm/gup.c:1504 [inline]
get_dump_page+0x146/0x2b0 mm/gup.c:2018
dump_user_range+0x126/0x910 fs/coredump.c:913
elf_core_dump+0x3b75/0x4490 fs/binfmt_elf.c:2142
do_coredump+0x1b73/0x2ab0 fs/coredump.c:764
get_signal+0x145e/0x1840 kernel/signal.c:2878
arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:309
exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:168
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:296
do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb68edcf0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc8b18d558 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffe5 RBX: 0000000000000003 RCX: 00007fb68edcf0f9
RDX: 0000000000000000 RSI: 0000000100000001 RDI: 0000000000000006
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000555500000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000f4240
R13: 00007ffc8b18d7c8 R14: 0000000000000001 R15: 00007ffc8b18d590
</TASK>


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#syz test: git://repo/address.git branch-or-commit-hash
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