linux-kernel - [syzbot] [jfs?] KASAN: null-ptr-deref Read in drop

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Message-ID: <66fcb7f9.050a0220.f28ec.04e8.GAE@google.com>
Date: Tue, 01 Oct 2024 20:03:21 -0700
From: syzbot <syzbot+de1498ff3a934ac5e8b4@...kaller.appspotmail.com>
To: brauner@...nel.org, jack@...e.cz, jfs-discussion@...ts.sourceforge.net, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	shaggy@...nel.org, syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk
Subject: [syzbot] [jfs?] KASAN: null-ptr-deref Read in drop_buffers (3)

Hello,

syzbot found the following issue on:

HEAD commit:    e32cde8d2bd7 Merge tag 'sched_ext-for-6.12-rc1-fixes-1' of..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17b18307980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=286b31f2cf1c36b5
dashboard link: https://syzkaller.appspot.com/bug?extid=de1498ff3a934ac5e8b4
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=10718307980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12f3939f980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-e32cde8d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9c681f5609bc/vmlinux-e32cde8d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/00b4d54de1d9/bzImage-e32cde8d.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/14b0b7eafa4c/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+de1498ff3a934ac5e8b4@...kaller.appspotmail.com

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: null-ptr-deref in buffer_busy fs/buffer.c:2881 [inline]
BUG: KASAN: null-ptr-deref in drop_buffers+0x6f/0x710 fs/buffer.c:2893
Read of size 4 at addr 0000000000000060 by task kswapd0/74

CPU: 0 UID: 0 PID: 74 Comm: kswapd0 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_report+0xe8/0x550 mm/kasan/report.c:491
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 buffer_busy fs/buffer.c:2881 [inline]
 drop_buffers+0x6f/0x710 fs/buffer.c:2893
 try_to_free_buffers+0x295/0x5f0 fs/buffer.c:2947
 shrink_folio_list+0x240c/0x8cc0 mm/vmscan.c:1432
 evict_folios+0x549b/0x7b50 mm/vmscan.c:4583
 try_to_shrink_lruvec+0x9ab/0xbb0 mm/vmscan.c:4778
 shrink_one+0x3b9/0x850 mm/vmscan.c:4816
 shrink_many mm/vmscan.c:4879 [inline]
 lru_gen_shrink_node mm/vmscan.c:4957 [inline]
 shrink_node+0x3799/0x3de0 mm/vmscan.c:5937
 kswapd_shrink_node mm/vmscan.c:6765 [inline]
 balance_pgdat mm/vmscan.c:6957 [inline]
 kswapd+0x1ca3/0x3700 mm/vmscan.c:7226
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
==================================================================


---
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