Subject: Re: [syzbot] [net?] KASAN: slab-use-after-free Read in unix_del_edges

From: syzbot <[email-masked]>
Date: Fri, 19 Apr 2024 14:13:01 -0700

Hello,

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

registered new interface driver rtsx_usb
[    7.654500][    T1] usbcore: registered new interface driver viperboard
[    7.656820][    T1] usbcore: registered new interface driver dln2
[    7.658229][    T1] usbcore: registered new interface driver pn533_usb
[    7.665094][    T1] nfcsim 0.2 initialized
[    7.666287][    T1] usbcore: registered new interface driver port100
[    7.667860][    T1] usbcore: registered new interface driver nfcmrvl
[    7.677894][    T1] Loading iSCSI transport class v2.0-870.
[    7.691826][    T1] virtio_scsi virtio0: 1/0/0 default/read/poll queues
[    7.700510][    T1] ------------[ cut here ]------------
[    7.701647][    T1] refcount_t: decrement hit 0; leaking memory.
[    7.702712][    T1] WARNING: CPU: 1 PID: 1 at lib/refcount.c:31 refcount_warn_saturate+0xfa/0x1d0
[    7.705030][    T1] Modules linked in:
[    7.705931][    T1] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.9.0-rc4-syzkaller-00895-g4cad4efa6eb2-dirty #0
[    7.707420][    T1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
[    7.708867][    T1] RIP: 0010:refcount_warn_saturate+0xfa/0x1d0
[    7.709787][    T1] Code: b2 00 00 00 e8 97 ee e6 fc 5b 5d c3 cc cc cc cc e8 8b ee e6 fc c6 05 92 84 e4 0a 01 90 48 c7 c7 80 33 1f 8c e8 f7 6a a9 fc 90 <0f> 0b 90 90 eb d9 e8 6b ee e6 fc c6 05 6f 84 e4 0a 01 90 48 c7 c7
[    7.712924][    T1] RSP: 0000:ffffc90000066e18 EFLAGS: 00010246
[    7.714098][    T1] RAX: 802fad55264ab500 RBX: ffff888146ad6b3c RCX: ffff8880166d0000
[    7.715583][    T1] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[    7.717186][    T1] RBP: 0000000000000004 R08: ffffffff81588082 R09: fffffbfff1c39b48
[    7.718689][    T1] R10: dffffc0000000000 R11: fffffbfff1c39b48 R12: ffffea0000850dc0
[    7.720446][    T1] R13: ffffea0000850dc8 R14: 1ffffd400010a1b9 R15: 0000000000000000
[    7.721919][    T1] FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
[    7.723283][    T1] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    7.724203][    T1] CR2: 0000000000000000 CR3: 000000000e134000 CR4: 00000000003506f0
[    7.725329][    T1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[    7.726405][    T1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[    7.727490][    T1] Call Trace:
[    7.727952][    T1]  <TASK>
[    7.728408][    T1]  ? __warn+0x163/0x4e0
[    7.729132][    T1]  ? refcount_warn_saturate+0xfa/0x1d0
[    7.729918][    T1]  ? report_bug+0x2b3/0x500
[    7.730722][    T1]  ? refcount_warn_saturate+0xfa/0x1d0
[    7.731598][    T1]  ? handle_bug+0x3e/0x70
[    7.732470][    T1]  ? exc_invalid_op+0x1a/0x50
[    7.733180][    T1]  ? asm_exc_invalid_op+0x1a/0x20
[    7.734321][    T1]  ? __warn_printk+0x292/0x360
[    7.735110][    T1]  ? refcount_warn_saturate+0xfa/0x1d0
[    7.736046][    T1]  ? refcount_warn_saturate+0xf9/0x1d0
[    7.737157][    T1]  __free_pages_ok+0xc60/0xd90
[    7.737974][    T1]  make_alloc_exact+0xa3/0xf0
[    7.739152][    T1]  vring_alloc_queue_split+0x20a/0x600
[    7.739921][    T1]  ? __pfx_vring_alloc_queue_split+0x10/0x10
[    7.740857][    T1]  ? vp_find_vqs+0x4c/0x4e0
[    7.742030][    T1]  ? virtscsi_probe+0x3ea/0xf60
[    7.743130][    T1]  ? virtio_dev_probe+0x991/0xaf0
[    7.744156][    T1]  ? really_probe+0x2b8/0xad0
[    7.745411][    T1]  ? driver_probe_device+0x50/0x430
[    7.746481][    T1]  vring_create_virtqueue_split+0xc6/0x310
[    7.747395][    T1]  ? ret_from_fork+0x4b/0x80
[    7.748185][    T1]  ? __pfx_vring_create_virtqueue_split+0x10/0x10
[    7.749718][    T1]  vring_create_virtqueue+0xca/0x110
[    7.750680][    T1]  ? __pfx_vp_notify+0x10/0x10
[    7.751352][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.752127][    T1]  setup_vq+0xe9/0x2d0
[    7.752740][    T1]  ? __pfx_vp_notify+0x10/0x10
[    7.753739][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.754582][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.755808][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.756624][    T1]  vp_setup_vq+0xbf/0x330
[    7.757294][    T1]  ? __pfx_vp_config_changed+0x10/0x10
[    7.758740][    T1]  ? ioread16+0x2f/0x90
[    7.759423][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.760184][    T1]  vp_find_vqs_msix+0x8b2/0xc80
[    7.761570][    T1]  vp_find_vqs+0x4c/0x4e0
[    7.762347][    T1]  virtscsi_init+0x8db/0xd00
[    7.763210][    T1]  ? __pfx_virtscsi_init+0x10/0x10
[    7.764163][    T1]  ? __pfx_default_calc_sets+0x10/0x10
[    7.765029][    T1]  ? scsi_host_alloc+0xa57/0xea0
[    7.765845][    T1]  ? vp_get+0xfd/0x140
[    7.766595][    T1]  virtscsi_probe+0x3ea/0xf60
[    7.767420][    T1]  ? __pfx_virtscsi_probe+0x10/0x10
[    7.768268][    T1]  ? kernfs_add_one+0x156/0x8b0
[    7.769025][    T1]  ? virtio_no_restricted_mem_acc+0x9/0x10
[    7.769838][    T1]  ? virtio_features_ok+0x10c/0x270
[    7.770612][    T1]  virtio_dev_probe+0x991/0xaf0
[    7.771348][    T1]  ? __pfx_virtio_dev_probe+0x10/0x10
[    7.772249][    T1]  really_probe+0x2b8/0xad0
[    7.773081][    T1]  __driver_probe_device+0x1a2/0x390
[    7.774142][    T1]  driver_probe_device+0x50/0x430
[    7.775055][    T1]  __driver_attach+0x45f/0x710
[    7.775738][    T1]  ? __pfx___driver_attach+0x10/0x10
[    7.777068][    T1]  bus_for_each_dev+0x239/0x2b0
[    7.778013][    T1]  ? __pfx___driver_attach+0x10/0x10
[    7.778935][    T1]  ? __pfx_bus_for_each_dev+0x10/0x10
[    7.779835][    T1]  ? do_raw_spin_unlock+0x13c/0x8b0
[    7.780678][    T1]  bus_add_driver+0x347/0x620
[    7.781572][    T1]  driver_register+0x23a/0x320
[    7.782416][    T1]  virtio_scsi_init+0x69/0xe0
[    7.783114][    T1]  ? __pfx_virtio_scsi_init+0x10/0x10
[    7.783862][    T1]  do_one_initcall+0x248/0x880
[    7.784838][    T1]  ? __pfx_virtio_scsi_init+0x10/0x10
[    7.785602][    T1]  ? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10
[    7.786590][    T1]  ? __pfx_do_one_initcall+0x10/0x10
[    7.787715][    T1]  ? __pfx_parse_args+0x10/0x10
[    7.788740][    T1]  ? do_initcalls+0x1c/0x80
[    7.789436][    T1]  ? rcu_is_watching+0x15/0xb0
[    7.790134][    T1]  do_initcall_level+0x157/0x210
[    7.791134][    T1]  do_initcalls+0x3f/0x80
[    7.791963][    T1]  kernel_init_freeable+0x435/0x5d0
[    7.792838][    T1]  ? __pfx_kernel_init_freeable+0x10/0x10
[    7.793797][    T1]  ? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10
[    7.794852][    T1]  ? __pfx_kernel_init+0x10/0x10
[    7.795572][    T1]  ? __pfx_kernel_init+0x10/0x10
[    7.796447][    T1]  ? __pfx_kernel_init+0x10/0x10
[    7.797205][    T1]  kernel_init+0x1d/0x2b0
[    7.797981][    T1]  ret_from_fork+0x4b/0x80
[    7.798980][    T1]  ? __pfx_kernel_init+0x10/0x10
[    7.799980][    T1]  ret_from_fork_asm+0x1a/0x30
[    7.801171][    T1]  </TASK>
[    7.801810][    T1] Kernel panic - not syncing: kernel: panic_on_warn set ...
[    7.802882][    T1] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.9.0-rc4-syzkaller-00895-g4cad4efa6eb2-dirty #0
[    7.804509][    T1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
[    7.804834][    T1] Call Trace:
[    7.804834][    T1]  <TASK>
[    7.804834][    T1]  dump_stack_lvl+0x241/0x360
[    7.804834][    T1]  ? __pfx_dump_stack_lvl+0x10/0x10
[    7.804834][    T1]  ? __pfx__printk+0x10/0x10
[    7.804834][    T1]  ? _printk+0xd5/0x120
[    7.804834][    T1]  ? vscnprintf+0x5d/0x90
[    7.804834][    T1]  panic+0x349/0x860
[    7.804834][    T1]  ? __warn+0x172/0x4e0
[    7.804834][    T1]  ? __pfx_panic+0x10/0x10
[    7.804834][    T1]  ? show_trace_log_lvl+0x4e6/0x520
[    7.814431][    T1]  ? ret_from_fork_asm+0x1a/0x30
[    7.814431][    T1]  __warn+0x346/0x4e0
[    7.814431][    T1]  ? refcount_warn_saturate+0xfa/0x1d0
[    7.814431][    T1]  report_bug+0x2b3/0x500
[    7.814431][    T1]  ? refcount_warn_saturate+0xfa/0x1d0
[    7.814431][    T1]  handle_bug+0x3e/0x70
[    7.814431][    T1]  exc_invalid_op+0x1a/0x50
[    7.814431][    T1]  asm_exc_invalid_op+0x1a/0x20
[    7.814431][    T1] RIP: 0010:refcount_warn_saturate+0xfa/0x1d0
[    7.814431][    T1] Code: b2 00 00 00 e8 97 ee e6 fc 5b 5d c3 cc cc cc cc e8 8b ee e6 fc c6 05 92 84 e4 0a 01 90 48 c7 c7 80 33 1f 8c e8 f7 6a a9 fc 90 <0f> 0b 90 90 eb d9 e8 6b ee e6 fc c6 05 6f 84 e4 0a 01 90 48 c7 c7
[    7.814431][    T1] RSP: 0000:ffffc90000066e18 EFLAGS: 00010246
[    7.824572][    T1] RAX: 802fad55264ab500 RBX: ffff888146ad6b3c RCX: ffff8880166d0000
[    7.824572][    T1] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[    7.824572][    T1] RBP: 0000000000000004 R08: ffffffff81588082 R09: fffffbfff1c39b48
[    7.824572][    T1] R10: dffffc0000000000 R11: fffffbfff1c39b48 R12: ffffea0000850dc0
[    7.824572][    T1] R13: ffffea0000850dc8 R14: 1ffffd400010a1b9 R15: 0000000000000000
[    7.824572][    T1]  ? __warn_printk+0x292/0x360
[    7.824572][    T1]  ? refcount_warn_saturate+0xf9/0x1d0
[    7.824572][    T1]  __free_pages_ok+0xc60/0xd90
[    7.824572][    T1]  make_alloc_exact+0xa3/0xf0
[    7.824572][    T1]  vring_alloc_queue_split+0x20a/0x600
[    7.824572][    T1]  ? __pfx_vring_alloc_queue_split+0x10/0x10
[    7.834413][    T1]  ? vp_find_vqs+0x4c/0x4e0
[    7.834413][    T1]  ? virtscsi_probe+0x3ea/0xf60
[    7.834413][    T1]  ? virtio_dev_probe+0x991/0xaf0
[    7.834413][    T1]  ? really_probe+0x2b8/0xad0
[    7.834413][    T1]  ? driver_probe_device+0x50/0x430
[    7.834413][    T1]  vring_create_virtqueue_split+0xc6/0x310
[    7.834413][    T1]  ? ret_from_fork+0x4b/0x80
[    7.834413][    T1]  ? __pfx_vring_create_virtqueue_split+0x10/0x10
[    7.834413][    T1]  vring_create_virtqueue+0xca/0x110
[    7.834413][    T1]  ? __pfx_vp_notify+0x10/0x10
[    7.834413][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.834413][    T1]  setup_vq+0xe9/0x2d0
[    7.834413][    T1]  ? __pfx_vp_notify+0x10/0x10
[    7.844326][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.844326][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.844326][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.844326][    T1]  vp_setup_vq+0xbf/0x330
[    7.844326][    T1]  ? __pfx_vp_config_changed+0x10/0x10
[    7.844326][    T1]  ? ioread16+0x2f/0x90
[    7.844326][    T1]  ? __pfx_virtscsi_ctrl_done+0x10/0x10
[    7.844326][    T1]  vp_find_vqs_msix+0x8b2/0xc80
[    7.844326][    T1]  vp_find_vqs+0x4c/0x4e0
[    7.844326][    T1]  virtscsi_init+0x8db/0xd00
[    7.844326][    T1]  ? __pfx_virtscsi_init+0x10/0x10
[    7.844326][    T1]  ? __pfx_default_calc_sets+0x10/0x10
[    7.844326][    T1]  ? scsi_host_alloc+0xa57/0xea0
[    7.844326][    T1]  ? vp_get+0xfd/0x140
[    7.854405][    T1]  virtscsi_probe+0x3ea/0xf60
[    7.854405][    T1]  ? __pfx_virtscsi_probe+0x10/0x10
[    7.854405][    T1]  ? kernfs_add_one+0x156/0x8b0
[    7.854405][    T1]  ? virtio_no_restricted_mem_acc+0x9/0x10
[    7.854405][    T1]  ? virtio_features_ok+0x10c/0x270
[    7.854405][    T1]  virtio_dev_probe+0x991/0xaf0
[    7.854405][    T1]  ? __pfx_virtio_dev_probe+0x10/0x10
[    7.854405][    T1]  really_probe+0x2b8/0xad0
[    7.854405][    T1]  __driver_probe_device+0x1a2/0x390
[    7.854405][    T1]  driver_probe_device+0x50/0x430
[    7.854405][    T1]  __driver_attach+0x45f/0x710
[    7.854405][    T1]  ? __pfx___driver_attach+0x10/0x10
[    7.854405][    T1]  bus_for_each_dev+0x239/0x2b0
[    7.864323][    T1]  ? __pfx___driver_attach+0x10/0x10
[    7.864323][    T1]  ? __pfx_bus_for_each_dev+0x10/0x10
[    7.864323][    T1]  ? do_raw_spin_unlock+0x13c/0x8b0
[    7.864323][    T1]  bus_add_driver+0x347/0x620
[    7.864323][    T1]  driver_register+0x23a/0x320
[    7.864323][    T1]  virtio_scsi_init+0x69/0xe0
[    7.864323][    T1]  ? __pfx_virtio_scsi_init+0x10/0x10
[    7.864323][    T1]  do_one_initcall+0x248/0x880
[    7.864323][    T1]  ? __pfx_virtio_scsi_init+0x10/0x10
[    7.864323][    T1]  ? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10
[    7.864323][    T1]  ? __pfx_do_one_initcall+0x10/0x10
[    7.864323][    T1]  ? __pfx_parse_args+0x10/0x10
[    7.864323][    T1]  ? do_initcalls+0x1c/0x80
[    7.864323][    T1]  ? rcu_is_watching+0x15/0xb0
[    7.874391][    T1]  do_initcall_level+0x157/0x210
[    7.874391][    T1]  do_initcalls+0x3f/0x80
[    7.874391][    T1]  kernel_init_freeable+0x435/0x5d0
[    7.874391][    T1]  ? __pfx_kernel_init_freeable+0x10/0x10
[    7.874391][    T1]  ? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10
[    7.874391][    T1]  ? __pfx_kernel_init+0x10/0x10
[    7.874391][    T1]  ? __pfx_kernel_init+0x10/0x10
[    7.874391][    T1]  ? __pfx_kernel_init+0x10/0x10
[    7.874391][    T1]  kernel_init+0x1d/0x2b0
[    7.874391][    T1]  ret_from_fork+0x4b/0x80
[    7.874391][    T1]  ? __pfx_kernel_init+0x10/0x10
[    7.874391][    T1]  ret_from_fork_asm+0x1a/0x30
[    7.874391][    T1]  </TASK>
[    7.884330][    T1] Kernel Offset: disabled
[    7.884330][    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/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs/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/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-build3954342966=/tmp/go-build -gno-record-gcc-switches'

git status (err=<nil>)
HEAD detached at af24b0505
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=af24b0505c748561efb50f1d03c824d6642f6c0b -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240418-062732'" "-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=af24b0505c748561efb50f1d03c824d6642f6c0b -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240418-062732'" "-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=af24b0505c748561efb50f1d03c824d6642f6c0b -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240418-062732'" "-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=\"af24b0505c748561efb50f1d03c824d6642f6c0b\"

Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=11617880980000

Tested on:

commit:         4cad4efa Merge branch 'net-neigh-rcu'
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git main
kernel config:  https://syzkaller.appspot.com/x/.config?x=ecd971c4c871c35d
dashboard link: https://syzkaller.appspot.com/bug?extid=f3f3eef1d2100200e593
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15ef206f180000