WARNING in __folio_start_writeback

------------[ cut here ]------------
WARNING: ./include/linux/backing-dev.h:243 at inode_to_wb include/linux/backing-dev.h:239 [inline], CPU#1: kworker/u8:4/59
WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x8e7/0xa50 mm/page-writeback.c:3033, CPU#1: kworker/u8:4/59
Modules linked in:
CPU: 1 UID: 0 PID: 59 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:inode_to_wb include/linux/backing-dev.h:239 [inline]
RIP: 0010:__folio_start_writeback+0x8e7/0xa50 mm/page-writeback.c:3033
Code: 8b 05 2d 17 c8 10 48 3b 84 24 20 01 00 00 75 3b 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 10 5d 88 09 cc e8 1a fa c5 ff 90 <0f> 0b 90 e9 e5 fb ff ff e8 0c fa c5 ff 48 c7 c7 20 ff 3f 8e 4c 89
RSP: 0018:ffffc9000210eea0 EFLAGS: 00010293
RAX: ffffffff81fab916 RBX: ffffea000506f4c0 RCX: ffff88801c789e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000210f010 R08: ffffc9000210ef97 R09: 0000000000000000
R10: ffffc9000210ef80 R11: fffff52000421df3 R12: ffffea000506f4c8
R13: 0000000000000000 R14: ffff888148c9f000 R15: ffff888148c9ede0
FS:  0000000000000000(0000) GS:ffff888125af3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056206b42d168 CR3: 000000000e138000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __block_write_full_folio+0x75f/0xe10 fs/buffer.c:1928
 blkdev_writepages+0xd1/0x170 block/fops.c:484
 do_writepages+0x32e/0x550 mm/page-writeback.c:2604
 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1680
 writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047
 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158
 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
 wb_do_writeback fs/fs-writeback.c:2315 [inline]
 wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x47c/0x820 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


[   65.978951][   T59] ------------[ cut here ]------------
[   65.984565][   T59] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x8e7/0xa50, CPU#1: kworker/u8:4/59
[   65.996138][   T59] Modules linked in:
[   66.000210][   T59] CPU: 1 UID: 0 PID: 59 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) 
[   66.009629][   T59] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[   66.019860][   T59] Workqueue: writeback wb_workfn (flush-8:0)
[   66.026045][   T59] RIP: 0010:__folio_start_writeback+0x8e7/0xa50
[   66.032523][   T59] Code: 8b 05 2d 17 c8 10 48 3b 84 24 20 01 00 00 75 3b 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 10 5d 88 09 cc e8 1a fa c5 ff 90 <0f> 0b 90 e9 e5 fb ff ff e8 0c fa c5 ff 48 c7 c7 20 ff 3f 8e 4c 89
[   66.052498][   T59] RSP: 0018:ffffc9000210eea0 EFLAGS: 00010293
[   66.059017][   T59] RAX: ffffffff81fab916 RBX: ffffea000506f4c0 RCX: ffff88801c789e00
[   66.067102][   T59] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[   66.075417][   T59] RBP: ffffc9000210f010 R08: ffffc9000210ef97 R09: 0000000000000000
[   66.083846][   T59] R10: ffffc9000210ef80 R11: fffff52000421df3 R12: ffffea000506f4c8
[   66.091945][   T59] R13: 0000000000000000 R14: ffff888148c9f000 R15: ffff888148c9ede0
[   66.100236][   T59] FS:  0000000000000000(0000) GS:ffff888125af3000(0000) knlGS:0000000000000000
[   66.109434][   T59] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   66.116076][   T59] CR2: 000056206b42d168 CR3: 000000000e138000 CR4: 00000000003526f0
[   66.124113][   T59] Call Trace:
[   66.127408][   T59]  <TASK>
[   66.130595][   T59]  ? __pfx___folio_start_writeback+0x10/0x10
[   66.136598][   T59]  ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[   66.142754][   T59]  ? stack_trace_save+0x9c/0xe0
[   66.147622][   T59]  __block_write_full_folio+0x75f/0xe10
[   66.153223][   T59]  ? __pfx_blkdev_get_block+0x10/0x10
[   66.158635][   T59]  blkdev_writepages+0xd1/0x170
[   66.163491][   T59]  ? __pfx_blkdev_writepages+0x10/0x10
[   66.169214][   T59]  ? __pfx_blkdev_writepages+0x10/0x10
[   66.174681][   T59]  do_writepages+0x32e/0x550
[   66.179463][   T59]  __writeback_single_inode+0x145/0xff0
[   66.185207][   T59]  ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[   66.191278][   T59]  writeback_sb_inodes+0x6c7/0x1010
[   66.196508][   T59]  ? __pfx_writeback_sb_inodes+0x10/0x10
[   66.202453][   T59]  ? __pfx_down_read_trylock+0x10/0x10
[   66.207981][   T59]  ? __pfx___up_read+0x10/0x10
[   66.212905][   T59]  __writeback_inodes_wb+0x111/0x240
[   66.218239][   T59]  wb_writeback+0x44f/0xaf0
[   66.223237][   T59]  ? queue_io+0x321/0x590
[   66.227783][   T59]  ? __pfx_wb_writeback+0x10/0x10
[   66.233031][   T59]  wb_workfn+0xaef/0xef0
[   66.237292][   T59]  ? __pfx_wb_workfn+0x10/0x10
[   66.242122][   T59]  ? __lock_acquire+0xab9/0xd20
[   66.247098][   T59]  ? process_scheduled_works+0x9ef/0x17b0
[   66.252907][   T59]  ? _raw_spin_unlock_irq+0x23/0x50
[   66.258324][   T59]  ? process_scheduled_works+0x9ef/0x17b0
[   66.264222][   T59]  ? process_scheduled_works+0x9ef/0x17b0
[   66.270021][   T59]  process_scheduled_works+0xade/0x17b0
[   66.275704][   T59]  ? __pfx_process_scheduled_works+0x10/0x10
[   66.281788][   T59]  worker_thread+0x8a0/0xda0
[   66.286444][   T59]  kthread+0x70e/0x8a0
[   66.290648][   T59]  ? __pfx_worker_thread+0x10/0x10
[   66.295957][   T59]  ? __pfx_kthread+0x10/0x10
[   66.300624][   T59]  ? _raw_spin_unlock_irq+0x23/0x50
[   66.305925][   T59]  ? lockdep_hardirqs_on+0x9c/0x150
[   66.311200][   T59]  ? __pfx_kthread+0x10/0x10
[   66.315814][   T59]  ret_from_fork+0x47c/0x820
[   66.320557][   T59]  ? __pfx_ret_from_fork+0x10/0x10
[   66.325692][   T59]  ? __switch_to_asm+0x39/0x70
[   66.330707][   T59]  ? __switch_to_asm+0x33/0x70
[   66.335498][   T59]  ? __pfx_kthread+0x10/0x10
[   66.340228][   T59]  ret_from_fork_asm+0x1a/0x30
[   66.345049][   T59]  </TASK>
[   66.348065][   T59] Kernel panic - not syncing: kernel: panic_on_warn set ...
[   66.355331][   T59] CPU: 1 UID: 0 PID: 59 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) 
[   66.364698][   T59] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[   66.374849][   T59] Workqueue: writeback wb_workfn (flush-8:0)
[   66.380849][   T59] Call Trace:
[   66.384167][   T59]  <TASK>
[   66.387105][   T59]  dump_stack_lvl+0x99/0x250
[   66.391700][   T59]  ? __asan_memcpy+0x40/0x70
[   66.396355][   T59]  ? __pfx_dump_stack_lvl+0x10/0x10
[   66.401676][   T59]  ? __pfx__printk+0x10/0x10
[   66.406464][   T59]  vpanic+0x229/0x6d0
[   66.410477][   T59]  ? __pfx_vpanic+0x10/0x10
[   66.414972][   T59]  ? is_bpf_text_address+0x292/0x2b0
[   66.420248][   T59]  ? is_bpf_text_address+0x26/0x2b0
[   66.425449][   T59]  panic+0xb9/0xc0
[   66.429236][   T59]  ? __pfx_panic+0x10/0x10
[   66.433680][   T59]  ? ret_from_fork_asm+0x1a/0x30
[   66.438627][   T59]  __warn+0x334/0x4c0
[   66.442890][   T59]  ? __folio_start_writeback+0x8e7/0xa50
[   66.448623][   T59]  ? __folio_start_writeback+0x8e7/0xa50
[   66.454279][   T59]  report_bug+0x2be/0x4f0
[   66.458605][   T59]  ? __folio_start_writeback+0x8e7/0xa50
[   66.464314][   T59]  ? __folio_start_writeback+0x8e7/0xa50
[   66.469940][   T59]  ? __folio_start_writeback+0x8e9/0xa50
[   66.475660][   T59]  handle_bug+0x84/0x160
[   66.480009][   T59]  exc_invalid_op+0x1a/0x50
[   66.484504][   T59]  asm_exc_invalid_op+0x1a/0x20
[   66.489342][   T59] RIP: 0010:__folio_start_writeback+0x8e7/0xa50
[   66.495649][   T59] Code: 8b 05 2d 17 c8 10 48 3b 84 24 20 01 00 00 75 3b 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 10 5d 88 09 cc e8 1a fa c5 ff 90 <0f> 0b 90 e9 e5 fb ff ff e8 0c fa c5 ff 48 c7 c7 20 ff 3f 8e 4c 89
[   66.515334][   T59] RSP: 0018:ffffc9000210eea0 EFLAGS: 00010293
[   66.521504][   T59] RAX: ffffffff81fab916 RBX: ffffea000506f4c0 RCX: ffff88801c789e00
[   66.529471][   T59] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[   66.537433][   T59] RBP: ffffc9000210f010 R08: ffffc9000210ef97 R09: 0000000000000000
[   66.545391][   T59] R10: ffffc9000210ef80 R11: fffff52000421df3 R12: ffffea000506f4c8
[   66.553606][   T59] R13: 0000000000000000 R14: ffff888148c9f000 R15: ffff888148c9ede0
[   66.561672][   T59]  ? __folio_start_writeback+0x8e6/0xa50
[   66.567323][   T59]  ? __pfx___folio_start_writeback+0x10/0x10
[   66.573504][   T59]  ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[   66.579566][   T59]  ? stack_trace_save+0x9c/0xe0
[   66.584492][   T59]  __block_write_full_folio+0x75f/0xe10
[   66.590291][   T59]  ? __pfx_blkdev_get_block+0x10/0x10
[   66.595674][   T59]  blkdev_writepages+0xd1/0x170
[   66.600731][   T59]  ? __pfx_blkdev_writepages+0x10/0x10
[   66.606204][   T59]  ? __pfx_blkdev_writepages+0x10/0x10
[   66.611822][   T59]  do_writepages+0x32e/0x550
[   66.616850][   T59]  __writeback_single_inode+0x145/0xff0
[   66.622489][   T59]  ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[   66.628611][   T59]  writeback_sb_inodes+0x6c7/0x1010
[   66.633916][   T59]  ? __pfx_writeback_sb_inodes+0x10/0x10
[   66.639649][   T59]  ? __pfx_down_read_trylock+0x10/0x10
[   66.645203][   T59]  ? __pfx___up_read+0x10/0x10
[   66.649967][   T59]  __writeback_inodes_wb+0x111/0x240
[   66.655287][   T59]  wb_writeback+0x44f/0xaf0
[   66.660082][   T59]  ? queue_io+0x321/0x590
[   66.664648][   T59]  ? __pfx_wb_writeback+0x10/0x10
[   66.669684][   T59]  wb_workfn+0xaef/0xef0
[   66.673933][   T59]  ? __pfx_wb_workfn+0x10/0x10
[   66.678688][   T59]  ? __lock_acquire+0xab9/0xd20
[   66.683545][   T59]  ? process_scheduled_works+0x9ef/0x17b0
[   66.689265][   T59]  ? _raw_spin_unlock_irq+0x23/0x50
[   66.694550][   T59]  ? process_scheduled_works+0x9ef/0x17b0
[   66.700524][   T59]  ? process_scheduled_works+0x9ef/0x17b0
[   66.706236][   T59]  process_scheduled_works+0xade/0x17b0
[   66.711827][   T59]  ? __pfx_process_scheduled_works+0x10/0x10
[   66.718001][   T59]  worker_thread+0x8a0/0xda0
[   66.722606][   T59]  kthread+0x70e/0x8a0
[   66.726681][   T59]  ? __pfx_worker_thread+0x10/0x10
[   66.731773][   T59]  ? __pfx_kthread+0x10/0x10
[   66.736351][   T59]  ? _raw_spin_unlock_irq+0x23/0x50
[   66.741612][   T59]  ? lockdep_hardirqs_on+0x9c/0x150
[   66.746821][   T59]  ? __pfx_kthread+0x10/0x10
[   66.751517][   T59]  ret_from_fork+0x47c/0x820
[   66.756198][   T59]  ? __pfx_ret_from_fork+0x10/0x10
[   66.761320][   T59]  ? __switch_to_asm+0x39/0x70
[   66.766164][   T59]  ? __switch_to_asm+0x33/0x70
[   66.770933][   T59]  ? __pfx_kthread+0x10/0x10
[   66.775518][   T59]  ret_from_fork_asm+0x1a/0x30
[   66.780286][   T59]  </TASK>
[   66.783744][   T59] Kernel Offset: disabled
[   66.788156][   T59] Rebooting in 86400 seconds..


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1326872767=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs-2/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs-2/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs-2/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.4'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 3fd2ea69e0
nothing to commit, working tree clean


go list -f '{{.Stale}}' ./sys/syz-sysgen | grep -q false || go install ./sys/syz-sysgen
make .descriptions
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=3fd2ea69e05557e7e0fef9b68263b4150670671c -X 'github.com/google/syzkaller/prog.gitRevisionDate=20210812-202438'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-fuzzer github.com/google/syzkaller/syz-fuzzer
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=3fd2ea69e05557e7e0fef9b68263b4150670671c -X 'github.com/google/syzkaller/prog.gitRevisionDate=20210812-202438'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=3fd2ea69e05557e7e0fef9b68263b4150670671c -X 'github.com/google/syzkaller/prog.gitRevisionDate=20210812-202438'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-stress github.com/google/syzkaller/tools/syz-stress
mkdir -p ./bin/linux_amd64
gcc -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -static -fpermissive -w -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"3fd2ea69e05557e7e0fef9b68263b4150670671c\"