[syzbot] KASAN: stack-out-of-bounds Read in xfs_buf_lock

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    830b3c68c1fb Linux 6.1
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1058e613880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=81ba923a020d4bf2
dashboard link: https://syzkaller.appspot.com/bug?extid=0bc698a422b5e4ac988c
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0bc698a422b5e4ac988c@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: stack-out-of-bounds in instrument_atomic_read include/linux/instrumented.h:72 [inline]
BUG: KASAN: stack-out-of-bounds in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
BUG: KASAN: stack-out-of-bounds in xfs_buf_lock+0xd0/0x750 fs/xfs/xfs_buf.c:1118
Read of size 4 at addr ffffc90003bb7bec by task kswapd0/137

CPU: 0 PID: 137 Comm: kswapd0 Not tainted 6.1.0-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15e/0x461 mm/kasan/report.c:395
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:495
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x141/0x190 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 xfs_buf_lock+0xd0/0x750 fs/xfs/xfs_buf.c:1118
 xfs_buf_delwri_submit_buffers+0x131/0xae0 fs/xfs/xfs_buf.c:2164
 xfs_buf_delwri_submit+0x8a/0x260 fs/xfs/xfs_buf.c:2242
 xfs_qm_shrink_scan fs/xfs/xfs_qm.c:514 [inline]
 xfs_qm_shrink_scan+0x1a7/0x370 fs/xfs/xfs_qm.c:495
 do_shrink_slab+0x464/0xce0 mm/vmscan.c:842
 shrink_slab+0x175/0x660 mm/vmscan.c:1002
 shrink_node_memcgs mm/vmscan.c:6112 [inline]
 shrink_node+0x93d/0x1f30 mm/vmscan.c:6141
 kswapd_shrink_node mm/vmscan.c:6930 [inline]
 balance_pgdat+0x8f5/0x1530 mm/vmscan.c:7120
 kswapd+0x70b/0xfc0 mm/vmscan.c:7380
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>

The buggy address belongs to the virtual mapping at
 [ffffc90003bb0000, ffffc90003bb9000) created by:
 kernel_clone+0xeb/0x980 kernel/fork.c:2671

The buggy address belongs to the physical page:
page:ffffea000112a0c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x44a83
memcg:ffff88801ef48d82
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff88801ef48d82
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 4100, tgid 4100 (syz-executor.3), ts 374197857049, free_ts 372703071778
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4291
 __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5558
 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285
 vm_area_alloc_pages mm/vmalloc.c:2975 [inline]
 __vmalloc_area_node mm/vmalloc.c:3043 [inline]
 __vmalloc_node_range+0x978/0x13c0 mm/vmalloc.c:3213
 alloc_thread_stack_node kernel/fork.c:311 [inline]
 dup_task_struct kernel/fork.c:974 [inline]
 copy_process+0x1566/0x7190 kernel/fork.c:2084
 kernel_clone+0xeb/0x980 kernel/fork.c:2671
 __do_sys_clone+0xba/0x100 kernel/fork.c:2812
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1509
 free_unref_page_prepare mm/page_alloc.c:3387 [inline]
 free_unref_page+0x1d/0x4d0 mm/page_alloc.c:3483
 __vunmap+0x85d/0xd30 mm/vmalloc.c:2713
 free_work+0x5c/0x80 mm/vmalloc.c:97
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Memory state around the buggy address:
 ffffc90003bb7a80: 00 00 00 00 00 f1 f1 f1 f1 00 00 f3 f3 00 00 00
 ffffc90003bb7b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90003bb7b80: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 04
                                                          ^
 ffffc90003bb7c00: f2 04 f2 00 f2 f2 f2 00 f3 f3 f3 00 00 00 00 00
 ffffc90003bb7c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


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