Re: [syzbot] [kernfs?] possible deadlock in kernfs_fop_llseek

syzbot
2024-04-05T15:37:03Z

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

viperboard
[ 8.144672][ T1] usbcore: registered new interface driver dln2
[ 8.146814][ T1] usbcore: registered new interface driver pn533_usb
[ 8.154721][ T1] nfcsim 0.2 initialized
[ 8.156856][ T1] usbcore: registered new interface driver port100
[ 8.158745][ T1] usbcore: registered new interface driver nfcmrvl
[ 8.168709][ T1] Loading iSCSI transport class v2.0-870.
[ 8.188275][ T1] virtio_scsi virtio0: 1/0/0 default/read/poll queues
[ 8.202624][ T1] ------------[ cut here ]------------
[ 8.204252][ T1] refcount_t: decrement hit 0; leaking memory.
[ 8.206219][ T1] WARNING: CPU: 0 PID: 1 at lib/refcount.c:31 refcount_warn_saturate+0xfa/0x1d0
[ 8.208638][ T1] Modules linked in:
[ 8.209556][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.9.0-rc1-syzkaller-00001-g70d370568b75 #0
[ 8.214301][ T1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
[ 8.217361][ T1] RIP: 0010:refcount_warn_saturate+0xfa/0x1d0
[ 8.218680][ T1] Code: b2 00 00 00 e8 77 99 f2 fc 5b 5d c3 cc cc cc cc e8 6b 99 f2 fc c6 05 11 1e f0 0a 01 90 48 c7 c7 e0 5e 1e 8c e8 b7 35 b5 fc 90 <0f> 0b 90 90 eb d9 e8 4b 99 f2 fc c6 05 ee 1d f0 0a 01 90 48 c7 c7
[ 8.223425][ T1] RSP: 0000:ffffc90000066e18 EFLAGS: 00010246
[ 8.225385][ T1] RAX: 1f757896feb95b00 RBX: ffff8881482a2d7c RCX: ffff888016ac8000
[ 8.227629][ T1] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 8.229990][ T1] RBP: 0000000000000004 R08: ffffffff8157ffe2 R09: fffffbfff1c396e0
[ 8.232520][ T1] R10: dffffc0000000000 R11: fffffbfff1c396e0 R12: ffffea000502cdc0
[ 8.234601][ T1] R13: ffffea000502cdc8 R14: 1ffffd4000a059b9 R15: 0000000000000000
[ 8.236876][ T1] FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
[ 8.239600][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 8.240914][ T1] CR2: ffff88823ffff000 CR3: 000000000e132000 CR4: 00000000003506f0
[ 8.243303][ T1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 8.245750][ T1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 8.247945][ T1] Call Trace:
[ 8.248964][ T1] <TASK>
[ 8.250217][ T1] ? __warn+0x163/0x4e0
[ 8.251589][ T1] ? refcount_warn_saturate+0xfa/0x1d0
[ 8.253743][ T1] ? report_bug+0x2b3/0x500
[ 8.254770][ T1] ? refcount_warn_saturate+0xfa/0x1d0
[ 8.256336][ T1] ? handle_bug+0x3e/0x70
[ 8.257030][ T1] ? exc_invalid_op+0x1a/0x50
[ 8.258667][ T1] ? asm_exc_invalid_op+0x1a/0x20
[ 8.259957][ T1] ? __warn_printk+0x292/0x360
[ 8.261215][ T1] ? refcount_warn_saturate+0xfa/0x1d0
[ 8.263208][ T1] ? refcount_warn_saturate+0xf9/0x1d0
[ 8.264293][ T1] __free_pages_ok+0xc54/0xd80
[ 8.265404][ T1] make_alloc_exact+0xa3/0xf0
[ 8.266560][ T1] vring_alloc_queue_split+0x20a/0x600
[ 8.267988][ T1] ? __pfx_vring_alloc_queue_split+0x10/0x10
[ 8.269965][ T1] ? vp_find_vqs+0x4c/0x4e0
[ 8.271058][ T1] ? virtscsi_probe+0x3ea/0xf60
[ 8.272057][ T1] ? virtio_dev_probe+0x991/0xaf0
[ 8.273466][ T1] ? really_probe+0x2b8/0xad0
[ 8.275102][ T1] ? driver_probe_device+0x50/0x430
[ 8.276174][ T1] vring_create_virtqueue_split+0xc6/0x310
[ 8.277826][ T1] ? ret_from_fork+0x4b/0x80
[ 8.279140][ T1] ? __pfx_vring_create_virtqueue_split+0x10/0x10
[ 8.281586][ T1] vring_create_virtqueue+0xca/0x110
[ 8.283311][ T1] ? __pfx_vp_notify+0x10/0x10
[ 8.285146][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.286554][ T1] setup_vq+0xe9/0x2d0
[ 8.287916][ T1] ? __pfx_vp_notify+0x10/0x10
[ 8.289684][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.291329][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.292741][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.294786][ T1] vp_setup_vq+0xbf/0x330
[ 8.296422][ T1] ? __pfx_vp_config_changed+0x10/0x10
[ 8.297504][ T1] ? ioread16+0x2f/0x90
[ 8.298989][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.300925][ T1] vp_find_vqs_msix+0x8b2/0xc80
[ 8.302291][ T1] vp_find_vqs+0x4c/0x4e0
[ 8.303546][ T1] virtscsi_init+0x8db/0xd00
[ 8.304820][ T1] ? __pfx_virtscsi_init+0x10/0x10
[ 8.305808][ T1] ? __pfx_default_calc_sets+0x10/0x10
[ 8.307015][ T1] ? scsi_host_alloc+0xa57/0xea0
[ 8.308290][ T1] ? vp_get+0xfd/0x140
[ 8.309405][ T1] virtscsi_probe+0x3ea/0xf60
[ 8.310389][ T1] ? __pfx_virtscsi_probe+0x10/0x10
[ 8.311500][ T1] ? kernfs_add_one+0x156/0x8b0
[ 8.312348][ T1] ? virtio_no_restricted_mem_acc+0x9/0x10
[ 8.313977][ T1] ? virtio_features_ok+0x10c/0x270
[ 8.314859][ T1] virtio_dev_probe+0x991/0xaf0
[ 8.315766][ T1] ? __pfx_virtio_dev_probe+0x10/0x10
[ 8.316886][ T1] really_probe+0x2b8/0xad0
[ 8.317711][ T1] __driver_probe_device+0x1a2/0x390
[ 8.318525][ T1] driver_probe_device+0x50/0x430
[ 8.319567][ T1] __driver_attach+0x45f/0x710
[ 8.320525][ T1] ? __pfx___driver_attach+0x10/0x10
[ 8.321841][ T1] bus_for_each_dev+0x239/0x2b0
[ 8.322872][ T1] ? __pfx___driver_attach+0x10/0x10
[ 8.324235][ T1] ? __pfx_bus_for_each_dev+0x10/0x10
[ 8.326127][ T1] ? do_raw_spin_unlock+0x13c/0x8b0
[ 8.327579][ T1] bus_add_driver+0x347/0x620
[ 8.328989][ T1] driver_register+0x23a/0x320
[ 8.330318][ T1] ? __pfx_virtio_scsi_init+0x10/0x10
[ 8.332178][ T1] virtio_scsi_init+0x65/0xe0
[ 8.333752][ T1] ? __pfx_virtio_scsi_init+0x10/0x10
[ 8.334950][ T1] do_one_initcall+0x248/0x880
[ 8.336015][ T1] ? __pfx_virtio_scsi_init+0x10/0x10
[ 8.337202][ T1] ? __pfx_do_one_initcall+0x10/0x10
[ 8.338254][ T1] ? lockdep_hardirqs_on_prepare+0x43d/0x780
[ 8.339378][ T1] ? __pfx_parse_args+0x10/0x10
[ 8.341464][ T1] ? do_initcalls+0x1c/0x80
[ 8.342223][ T1] ? rcu_is_watching+0x15/0xb0
[ 8.343161][ T1] do_initcall_level+0x157/0x210
[ 8.344252][ T1] do_initcalls+0x3f/0x80
[ 8.345400][ T1] kernel_init_freeable+0x435/0x5d0
[ 8.346571][ T1] ? __pfx_kernel_init_freeable+0x10/0x10
[ 8.349024][ T1] ? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10
[ 8.350664][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.352143][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.353430][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.354609][ T1] kernel_init+0x1d/0x2b0
[ 8.355433][ T1] ret_from_fork+0x4b/0x80
[ 8.356203][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.357092][ T1] ret_from_fork_asm+0x1a/0x30
[ 8.358282][ T1] </TASK>
[ 8.359166][ T1] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 8.360941][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.9.0-rc1-syzkaller-00001-g70d370568b75 #0
[ 8.363085][ T1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
[ 8.363411][ T1] Call Trace:
[ 8.363411][ T1] <TASK>
[ 8.363411][ T1] dump_stack_lvl+0x241/0x360
[ 8.363411][ T1] ? __pfx_dump_stack_lvl+0x10/0x10
[ 8.363411][ T1] ? __pfx__printk+0x10/0x10
[ 8.363411][ T1] ? _printk+0xd5/0x120
[ 8.363411][ T1] ? vscnprintf+0x5d/0x90
[ 8.363411][ T1] panic+0x349/0x860
[ 8.363411][ T1] ? __warn+0x172/0x4e0
[ 8.363411][ T1] ? __pfx_panic+0x10/0x10
[ 8.363411][ T1] ? show_trace_log_lvl+0x4e6/0x520
[ 8.363411][ T1] ? ret_from_fork_asm+0x1a/0x30
[ 8.363411][ T1] __warn+0x346/0x4e0
[ 8.363411][ T1] ? refcount_warn_saturate+0xfa/0x1d0
[ 8.363411][ T1] report_bug+0x2b3/0x500
[ 8.363411][ T1] ? refcount_warn_saturate+0xfa/0x1d0
[ 8.363411][ T1] handle_bug+0x3e/0x70
[ 8.363411][ T1] exc_invalid_op+0x1a/0x50
[ 8.363411][ T1] asm_exc_invalid_op+0x1a/0x20
[ 8.363411][ T1] RIP: 0010:refcount_warn_saturate+0xfa/0x1d0
[ 8.363411][ T1] Code: b2 00 00 00 e8 77 99 f2 fc 5b 5d c3 cc cc cc cc e8 6b 99 f2 fc c6 05 11 1e f0 0a 01 90 48 c7 c7 e0 5e 1e 8c e8 b7 35 b5 fc 90 <0f> 0b 90 90 eb d9 e8 4b 99 f2 fc c6 05 ee 1d f0 0a 01 90 48 c7 c7
[ 8.363411][ T1] RSP: 0000:ffffc90000066e18 EFLAGS: 00010246
[ 8.363411][ T1] RAX: 1f757896feb95b00 RBX: ffff8881482a2d7c RCX: ffff888016ac8000
[ 8.363411][ T1] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 8.363411][ T1] RBP: 0000000000000004 R08: ffffffff8157ffe2 R09: fffffbfff1c396e0
[ 8.363411][ T1] R10: dffffc0000000000 R11: fffffbfff1c396e0 R12: ffffea000502cdc0
[ 8.363411][ T1] R13: ffffea000502cdc8 R14: 1ffffd4000a059b9 R15: 0000000000000000
[ 8.363411][ T1] ? __warn_printk+0x292/0x360
[ 8.363411][ T1] ? refcount_warn_saturate+0xf9/0x1d0
[ 8.363411][ T1] __free_pages_ok+0xc54/0xd80
[ 8.363411][ T1] make_alloc_exact+0xa3/0xf0
[ 8.363411][ T1] vring_alloc_queue_split+0x20a/0x600
[ 8.363411][ T1] ? __pfx_vring_alloc_queue_split+0x10/0x10
[ 8.363411][ T1] ? vp_find_vqs+0x4c/0x4e0
[ 8.363411][ T1] ? virtscsi_probe+0x3ea/0xf60
[ 8.363411][ T1] ? virtio_dev_probe+0x991/0xaf0
[ 8.363411][ T1] ? really_probe+0x2b8/0xad0
[ 8.363411][ T1] ? driver_probe_device+0x50/0x430
[ 8.363411][ T1] vring_create_virtqueue_split+0xc6/0x310
[ 8.363411][ T1] ? ret_from_fork+0x4b/0x80
[ 8.363411][ T1] ? __pfx_vring_create_virtqueue_split+0x10/0x10
[ 8.363411][ T1] vring_create_virtqueue+0xca/0x110
[ 8.363411][ T1] ? __pfx_vp_notify+0x10/0x10
[ 8.363411][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.363411][ T1] setup_vq+0xe9/0x2d0
[ 8.363411][ T1] ? __pfx_vp_notify+0x10/0x10
[ 8.363411][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.363411][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.363411][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.363411][ T1] vp_setup_vq+0xbf/0x330
[ 8.363411][ T1] ? __pfx_vp_config_changed+0x10/0x10
[ 8.363411][ T1] ? ioread16+0x2f/0x90
[ 8.363411][ T1] ? __pfx_virtscsi_ctrl_done+0x10/0x10
[ 8.363411][ T1] vp_find_vqs_msix+0x8b2/0xc80
[ 8.363411][ T1] vp_find_vqs+0x4c/0x4e0
[ 8.363411][ T1] virtscsi_init+0x8db/0xd00
[ 8.363411][ T1] ? __pfx_virtscsi_init+0x10/0x10
[ 8.363411][ T1] ? __pfx_default_calc_sets+0x10/0x10
[ 8.363411][ T1] ? scsi_host_alloc+0xa57/0xea0
[ 8.363411][ T1] ? vp_get+0xfd/0x140
[ 8.363411][ T1] virtscsi_probe+0x3ea/0xf60
[ 8.363411][ T1] ? __pfx_virtscsi_probe+0x10/0x10
[ 8.363411][ T1] ? kernfs_add_one+0x156/0x8b0
[ 8.363411][ T1] ? virtio_no_restricted_mem_acc+0x9/0x10
[ 8.363411][ T1] ? virtio_features_ok+0x10c/0x270
[ 8.363411][ T1] virtio_dev_probe+0x991/0xaf0
[ 8.363411][ T1] ? __pfx_virtio_dev_probe+0x10/0x10
[ 8.363411][ T1] really_probe+0x2b8/0xad0
[ 8.363411][ T1] __driver_probe_device+0x1a2/0x390
[ 8.363411][ T1] driver_probe_device+0x50/0x430
[ 8.363411][ T1] __driver_attach+0x45f/0x710
[ 8.363411][ T1] ? __pfx___driver_attach+0x10/0x10
[ 8.363411][ T1] bus_for_each_dev+0x239/0x2b0
[ 8.363411][ T1] ? __pfx___driver_attach+0x10/0x10
[ 8.363411][ T1] ? __pfx_bus_for_each_dev+0x10/0x10
[ 8.363411][ T1] ? do_raw_spin_unlock+0x13c/0x8b0
[ 8.363411][ T1] bus_add_driver+0x347/0x620
[ 8.363411][ T1] driver_register+0x23a/0x320
[ 8.363411][ T1] ? __pfx_virtio_scsi_init+0x10/0x10
[ 8.363411][ T1] virtio_scsi_init+0x65/0xe0
[ 8.363411][ T1] ? __pfx_virtio_scsi_init+0x10/0x10
[ 8.363411][ T1] do_one_initcall+0x248/0x880
[ 8.363411][ T1] ? __pfx_virtio_scsi_init+0x10/0x10
[ 8.363411][ T1] ? __pfx_do_one_initcall+0x10/0x10
[ 8.363411][ T1] ? lockdep_hardirqs_on_prepare+0x43d/0x780
[ 8.363411][ T1] ? __pfx_parse_args+0x10/0x10
[ 8.363411][ T1] ? do_initcalls+0x1c/0x80
[ 8.363411][ T1] ? rcu_is_watching+0x15/0xb0
[ 8.363411][ T1] do_initcall_level+0x157/0x210
[ 8.363411][ T1] do_initcalls+0x3f/0x80
[ 8.363411][ T1] kernel_init_freeable+0x435/0x5d0
[ 8.363411][ T1] ? __pfx_kernel_init_freeable+0x10/0x10
[ 8.363411][ T1] ? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10
[ 8.363411][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.363411][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.363411][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.363411][ T1] kernel_init+0x1d/0x2b0
[ 8.363411][ T1] ret_from_fork+0x4b/0x80
[ 8.363411][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.363411][ T1] ret_from_fork_asm+0x1a/0x30
[ 8.363411][ T1] </TASK>
[ 8.363411][ T1] Kernel Offset: disabled
[ 8.363411][ T1] Rebooting in 86400 seconds..

syzkaller build log:
go env (err=<nil>)
GO111MODULE='auto'
GOARCH='amd64'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
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'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.21.4'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/syzkaller/jobs-2/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2829307758=/tmp/go-build -gno-record-gcc-switches'

git status (err=<nil>)
HEAD detached at 51c4dcff8
nothing to commit, working tree clean

tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' ./sys/syz-sysgen | grep -q false || go install ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=51c4dcff83b0574620c280cc5130ef59cc4a2e32 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240403-123700'" "-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=51c4dcff83b0574620c280cc5130ef59cc4a2e32 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240403-123700'" "-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=51c4dcff83b0574620c280cc5130ef59cc4a2e32 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240403-123700'" "-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 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -fpermissive -w -DGOOS_linux=1 -DGOARCH_amd64=1 \
-DHOSTGOOS_linux=1 -DGIT_REVISION=\"51c4dcff83b0574620c280cc5130ef59cc4a2e32\"

Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=16ae7ead180000

Tested on:

commit: 70d37056 kernfs: annotate different lockdep class for ..
git tree: https://github.com/amir73il/linux/ vfs-fixes
kernel config: https://syzkaller.appspot.com/x/.config?x=d45c08b2154c215d
dashboard link: https://syzkaller.appspot.com/bug?extid=9a5b0ced8b1bfb238b56
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.