[syzbot] [mm?] kernel BUG in add_to_swap

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d5b235ec8eab Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=13837dc1e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=f36ea342ce412b14
dashboard link: https://syzkaller.appspot.com/bug?extid=9c40fd6eff0f3277cc9e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/edab88544ce7/disk-d5b235ec.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d149255b78d/vmlinux-d5b235ec.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c3bfc66db2fc/Image-d5b235ec.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9c40fd...@syzkaller.appspotmail.com

raw: 05ffc00000480011 dead000000000100 dead000000000122 ffff0000d90d0aa1
raw: 0000000000020ffd 0000000000000000 00000002ffffffff ffff00012a670000
page dumped because: VM_BUG_ON_FOLIO(!folio_test_uptodate(folio))
------------[ cut here ]------------
kernel BUG at mm/swap_state.c:183!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 14071 Comm: syz-executor.3 Not tainted 6.7.0-rc5-syzkaller-gd5b235ec8eab #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : add_to_swap+0x1b4/0x1b8 mm/swap_state.c:183
lr : add_to_swap+0x1b4/0x1b8 mm/swap_state.c:183
sp : ffff80009b5d68e0
x29: ffff80009b5d68e0 x28: fffffc0004bf0a18 x27: fffffc0004bf0a08
x26: 0000000000000004 x25: dfff800000000000 x24: 05ffc00000480011
x23: 1fffff800097e140 x22: 1fffff800097e141 x21: dfff800000000000
x20: 05ffc00000480011 x19: fffffc0004bf0a00 x18: 1fffe000368261ce
x17: ffff80008e4ed000 x16: ffff800080317cac x15: 0000000000000001
x14: 1fffe00018eece00 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000040000 x10: 000000000003ffff x9 : ffff8000970a9000
x8 : 0000000000040000 x7 : ffff80008028f018 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000001 x3 : ffff80008027b600
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000041
Call trace:
add_to_swap+0x1b4/0x1b8 mm/swap_state.c:183
shrink_folio_list+0x1f70/0x4b0c mm/vmscan.c:1209
shrink_inactive_list mm/vmscan.c:1913 [inline]
shrink_list mm/vmscan.c:2154 [inline]
shrink_lruvec+0x12a4/0x27b4 mm/vmscan.c:5626
shrink_node_memcgs mm/vmscan.c:5812 [inline]
shrink_node+0xdec/0x226c mm/vmscan.c:5847
shrink_zones mm/vmscan.c:6086 [inline]
do_try_to_free_pages+0x5f8/0x14fc mm/vmscan.c:6148
try_to_free_mem_cgroup_pages+0x3a0/0xbac mm/vmscan.c:6463
try_charge_memcg+0x4a4/0x148c mm/memcontrol.c:2742
obj_cgroup_charge_pages mm/memcontrol.c:3255 [inline]
__memcg_kmem_charge_page+0x188/0x304 mm/memcontrol.c:3281
__alloc_pages+0x254/0x698 mm/page_alloc.c:4585
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
bpf_ringbuf_area_alloc kernel/bpf/ringbuf.c:122 [inline]
bpf_ringbuf_alloc+0x100/0x434 kernel/bpf/ringbuf.c:170
ringbuf_map_alloc+0x19c/0x288 kernel/bpf/ringbuf.c:204
map_create+0x6f4/0xd64 kernel/bpf/syscall.c:1210
__sys_bpf+0x204/0x5dc kernel/bpf/syscall.c:5365
__do_sys_bpf kernel/bpf/syscall.c:5487 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5485 [inline]
__arm64_sys_bpf+0x80/0x98 kernel/bpf/syscall.c:5485
__invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155
el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595
Code: f0050741 91218021 aa1303e0 97fcbfa7 (d4210000)
---[ end trace 0000000000000000 ]---


---
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[Matthew Wilcox]

On Tue, Dec 19, 2023 at 05:09:25AM -0800, syzbot wrote:
> raw: 05ffc00000480011 dead000000000100 dead000000000122 ffff0000d90d0aa1
> raw: 0000000000020ffd 0000000000000000 00000002ffffffff ffff00012a670000
> page dumped because: VM_BUG_ON_FOLIO(!folio_test_uptodate(folio))

The missing part of the dump:

page:0000000058ec4ec0 refcount:2 mapcount:0 mapping:0000000000000000 index:0x20ffd pfn:0x16fc28
memcg:ffff00012a670000
anon flags: 0x5ffc00000480011(locked|dirty|swapbacked|hwpoison|node=0|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()

raw: 05ffc00000480011 dead000000000100 dead000000000122 ffff0000d90d0aa1
raw: 0000000000020ffd 0000000000000000 00000002ffffffff ffff00012a670000
page dumped because: VM_BUG_ON_FOLIO(!folio_test_uptodate(folio))

I'm not sure how we get an anonymous dirty folio that's not uptodate.
It's order-0, so that doesn't implicate any of the recent positive-order
work.