Re: [syzbot] [net?] [bpf?] KMSAN: uninit-value in sock_hash_delete_elem

[syzbot <syzbot+c33bff5d5da1391df027@syzkaller.appspotmail.com>]

Hello,

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

 46.862565][    T1] IPI shorthand broadcast: enabled
[   48.390695][    T1] sched_clock: Marking stable (48370050826, 17960846)->(48402924943, -14913271)
[   49.493182][    T1] Timer migration: 1 hierarchy levels; 8 children per group; 0 crossnode level
[   49.645015][    T1] registered taskstats version 1
[   49.719060][    T1] Loading compiled-in X.509 certificates
[   49.757838][    T1] Loaded X.509 cert 'Build time autogenerated kernel key: 0721be491b560242240f4d386be31dadacd83fb9'
[   49.999690][    T1] zswap: loaded using pool lzo/zsmalloc
[   50.009346][    T1] Demotion targets for Node 0: null
[   50.014859][    T1] Demotion targets for Node 1: null
[   50.024245][    T1] Key type .fscrypt registered
[   50.029139][    T1] Key type fscrypt-provisioning registered
[   50.036215][    T1] kAFS: Red Hat AFS client v0.1 registering.
[   50.067479][    T1] Btrfs loaded, assert=on, ref-verify=on, zoned=yes, fsverity=yes
[   50.093752][    T1] Key type encrypted registered
[   50.098879][    T1] AppArmor: AppArmor sha256 policy hashing enabled
[   50.105629][    T1] ima: No TPM chip found, activating TPM-bypass!
[   50.112793][    T1] Loading compiled-in module X.509 certificates
[   50.155555][    T1] Loaded X.509 cert 'Build time autogenerated kernel key: 0721be491b560242240f4d386be31dadacd83fb9'
[   50.166713][    T1] ima: Allocated hash algorithm: sha256
[   50.172789][    T1] ima: No architecture policies found
[   50.179427][    T1] evm: Initialising EVM extended attributes:
[   50.185545][    T1] evm: security.selinux (disabled)
[   50.190767][    T1] evm: security.SMACK64 (disabled)
[   50.196020][    T1] evm: security.SMACK64EXEC (disabled)
[   50.201593][    T1] evm: security.SMACK64TRANSMUTE (disabled)
[   50.207535][    T1] evm: security.SMACK64MMAP (disabled)
[   50.213128][    T1] evm: security.apparmor
[   50.217595][    T1] evm: security.ima
[   50.221508][    T1] evm: security.capability
[   50.225972][    T1] evm: HMAC attrs: 0x1
[   50.234955][    T1] PM:   Magic number: 12:678:32
[   50.241542][    T1] tty ttydf: hash matches
[   50.247287][    T1] printk: legacy console [netcon0] enabled
[   50.254497][    T1] netconsole: network logging started
[   50.261482][    T1] gtp: GTP module loaded (pdp ctx size 128 bytes)
[   50.270457][    T1] rdma_rxe: loaded
[   50.276235][    T1] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[   50.295946][    T1] Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[   50.313521][    T1] Loaded X.509 cert 'wens: 61c038651aabdcf94bd0ac7ff06c7248db18c600'
[   50.322130][    T1] clk: Disabling unused clocks
[   50.327068][    T1] ALSA device list:
[   50.331121][    T1]   #0: Dummy 1
[   50.334711][    T1]   #1: Loopback 1
[   50.339143][    T1]   #2: Virtual MIDI Card 1
[   50.350432][    T1] md: Waiting for all devices to be available before autodetect
[   50.350717][   T25] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[   50.358332][    T1] md: If you don't use raid, use raid=noautodetect
[   50.358393][    T1] md: Autodetecting RAID arrays.
[   50.358434][    T1] md: autorun ...
[   50.358473][    T1] md: ... autorun DONE.
[   50.388342][   T25] platform regulatory.0: Falling back to sysfs fallback for: regulatory.db
[   50.481647][    T1] EXT4-fs (sda1): mounted filesystem 5941fea2-f5fa-4b4e-b5ef-9af118b27b95 ro with ordered data mode. Quota mode: none.
[   50.495006][    T1] VFS: Mounted root (ext4 filesystem) readonly on device 8:1.
[   50.507343][    T1] devtmpfs: mounted
[   50.770936][    T1] Freeing unused kernel image (initmem) memory: 36920K
[   50.782607][    T1] Write protecting the kernel read-only data: 260096k
[   50.830503][    T1] Freeing unused kernel image (rodata/data gap) memory: 1876K
[   52.482845][    T1] x86/mm: Checked W+X mappings: passed, no W+X pages found.
[   52.493217][    T1] x86/mm: Checking user space page tables
[   53.998271][    T1] x86/mm: Checked W+X mappings: passed, no W+X pages found.
[   54.007467][    T1] Failed to set sysctl parameter 'kernel.hung_task_all_cpu_backtrace=1': parameter not found
[   54.031284][    T1] Failed to set sysctl parameter 'max_rcu_stall_to_panic=1': parameter not found
[   54.043107][    T1] Run /sbin/init as init process
[   55.620910][ T4446] mount (4446) used greatest stack depth: 8144 bytes left
[   55.692569][ T4447] EXT4-fs (sda1): re-mounted 5941fea2-f5fa-4b4e-b5ef-9af118b27b95 r/w. Quota mode: none.
mount: mounting smackfs on /sys/fs/smackfs failed: No such file or directory
mount: mounting selinuxfs on /sys/fs/selinux failed: No such file or directory
[   56.030947][ T4450] mount (4450) used greatest stack depth: 5568 bytes left
Starting syslogd: OK
Starting acpid: OK
Starting klogd: OK
Running sysctl: OK
Populating /dev using udev: [   59.860978][ T4480] udevd[4480]: starting version 3.2.11
[   63.448534][ T4481] udevd[4481]: starting eudev-3.2.11
[   63.461355][ T4480] udevd (4480) used greatest stack depth: 5376 bytes left
done
Starting system message bus: done
Starting iptables: OK
Starting network: OK
Starting dhcpcd...
dhcpcd-9.4.1 starting
dev: loaded udev
DUID 00:04:c7:fd:4a:df:9d:a6:e9:60:55:7b:b4:5b:1f:77:00:5c
no interfaces have a carrier
forked to background, child pid 4694
[  111.282058][ T4695] 8021q: adding VLAN 0 to HW filter on device bond0
[  111.333940][ T4695] eql: remember to turn off Van-Jacobson compression on your slave devices
[  111.851180][   T25] cfg80211: failed to load regulatory.db
Starting sshd: OK


syzkaller

syzkaller login: [  113.999622][    C0] =====================================================
[  114.006947][    C0] BUG: KMSAN: uninit-value in receive_buf+0x25e3/0x5fd0
[  114.014214][    C0]  receive_buf+0x25e3/0x5fd0
[  114.019047][    C0]  virtnet_poll+0xd1c/0x23c0
[  114.023845][    C0]  __napi_poll+0xe7/0x980
[  114.028437][    C0]  net_rx_action+0x82a/0x1850
[  114.033296][    C0]  handle_softirqs+0x1ce/0x800
[  114.038238][    C0]  __irq_exit_rcu+0x68/0x120
[  114.042976][    C0]  irq_exit_rcu+0x12/0x20
[  114.047393][    C0]  common_interrupt+0x94/0xa0
[  114.052272][    C0]  asm_common_interrupt+0x2b/0x40
[  114.057547][    C0]  acpi_safe_halt+0x25/0x30
[  114.062420][    C0]  acpi_idle_do_entry+0x22/0x40
[  114.067438][    C0]  acpi_idle_enter+0xa1/0xc0
[  114.072234][    C0]  cpuidle_enter_state+0xcb/0x250
[  114.077501][    C0]  cpuidle_enter+0x7f/0xf0
[  114.082119][    C0]  do_idle+0x551/0x750
[  114.086349][    C0]  cpu_startup_entry+0x65/0x80
[  114.091272][    C0]  rest_init+0x1e8/0x260
[  114.095675][    C0]  start_kernel+0x92c/0xa70
[  114.100384][    C0]  x86_64_start_reservations+0x2e/0x30
[  114.106047][    C0]  x86_64_start_kernel+0x98/0xa0
[  114.111263][    C0]  common_startup_64+0x12c/0x137
[  114.116564][    C0] 
[  114.119010][    C0] Uninit was created at:
[  114.123471][    C0]  __alloc_pages_noprof+0x9d6/0xe70
[  114.128864][    C0]  alloc_pages_mpol_noprof+0x299/0x990
[  114.134532][    C0]  alloc_pages_noprof+0x1bf/0x1e0
[  114.139774][    C0]  skb_page_frag_refill+0x2bf/0x7c0
[  114.145167][    C0]  virtnet_rq_alloc+0x43/0xbb0
[  114.150208][    C0]  try_fill_recv+0x3f0/0x2f50
[  114.155069][    C0]  virtnet_open+0x1cc/0xb00
[  114.159814][    C0]  __dev_open+0x546/0x6f0
[  114.164339][    C0]  __dev_change_flags+0x309/0x9a0
[  114.169581][    C0]  dev_change_flags+0x8e/0x1d0
[  114.174515][    C0]  devinet_ioctl+0x13ec/0x22c0
[  114.179650][    C0]  inet_ioctl+0x4bd/0x6d0
[  114.184217][    C0]  sock_do_ioctl+0xb7/0x540
[  114.188902][    C0]  sock_ioctl+0x727/0xd70
[  114.193366][    C0]  __se_sys_ioctl+0x261/0x450
[  114.198305][    C0]  __x64_sys_ioctl+0x96/0xe0
[  114.203035][    C0]  x64_sys_call+0x18c0/0x3b90
[  114.208102][    C0]  do_syscall_64+0xcd/0x1e0
[  114.212760][    C0]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  114.218840][    C0] 
[  114.221299][    C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.10.0-rc3-syzkaller-00022-g90302a82de09 #0
[  114.231270][    C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
[  114.241487][    C0] =====================================================
[  114.248662][    C0] Disabling lock debugging due to kernel taint
[  114.254904][    C0] Kernel panic - not syncing: kmsan.panic set ...
[  114.261375][    C0] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G    B              6.10.0-rc3-syzkaller-00022-g90302a82de09 #0
[  114.272855][    C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
[  114.283040][    C0] Call Trace:
[  114.286385][    C0]  <IRQ>
[  114.289279][    C0]  dump_stack_lvl+0x216/0x2d0
[  114.294091][    C0]  ? kmsan_get_shadow_origin_ptr+0x4d/0xb0
[  114.300049][    C0]  dump_stack+0x1e/0x30
[  114.304329][    C0]  panic+0x4e2/0xcd0
[  114.308315][    C0]  ? kmsan_get_metadata+0xb1/0x1d0
[  114.313630][    C0]  kmsan_report+0x2d5/0x2e0
[  114.318244][    C0]  ? kmsan_get_shadow_origin_ptr+0x4d/0xb0
[  114.324165][    C0]  ? kmsan_get_metadata+0x146/0x1d0
[  114.329472][    C0]  ? __msan_warning+0x95/0x120
[  114.334350][    C0]  ? receive_buf+0x25e3/0x5fd0
[  114.339235][    C0]  ? virtnet_poll+0xd1c/0x23c0
[  114.344129][    C0]  ? __napi_poll+0xe7/0x980
[  114.348859][    C0]  ? net_rx_action+0x82a/0x1850
[  114.353823][    C0]  ? handle_softirqs+0x1ce/0x800
[  114.358872][    C0]  ? __irq_exit_rcu+0x68/0x120
[  114.363742][    C0]  ? irq_exit_rcu+0x12/0x20
[  114.368333][    C0]  ? common_interrupt+0x94/0xa0
[  114.373295][    C0]  ? asm_common_interrupt+0x2b/0x40
[  114.378595][    C0]  ? acpi_safe_halt+0x25/0x30
[  114.383390][    C0]  ? acpi_idle_do_entry+0x22/0x40
[  114.388528][    C0]  ? acpi_idle_enter+0xa1/0xc0
[  114.393384][    C0]  ? cpuidle_enter_state+0xcb/0x250
[  114.398680][    C0]  ? cpuidle_enter+0x7f/0xf0
[  114.403397][    C0]  ? do_idle+0x551/0x750
[  114.407738][    C0]  ? cpu_startup_entry+0x65/0x80
[  114.412803][    C0]  ? rest_init+0x1e8/0x260
[  114.417343][    C0]  ? start_kernel+0x92c/0xa70
[  114.422151][    C0]  ? x86_64_start_reservations+0x2e/0x30
[  114.427913][    C0]  ? x86_64_start_kernel+0x98/0xa0
[  114.433238][    C0]  ? common_startup_64+0x12c/0x137
[  114.438556][    C0]  ? kmsan_internal_memmove_metadata+0x17b/0x230
[  114.444994][    C0]  ? kmsan_get_metadata+0x146/0x1d0
[  114.450384][    C0]  ? kmsan_get_metadata+0x146/0x1d0
[  114.455777][    C0]  ? page_to_skb+0xdae/0x1620
[  114.460590][    C0]  ? kmsan_get_metadata+0x146/0x1d0
[  114.466005][    C0]  __msan_warning+0x95/0x120
[  114.470702][    C0]  receive_buf+0x25e3/0x5fd0
[  114.475415][    C0]  ? kmsan_get_metadata+0x146/0x1d0
[  114.480723][    C0]  ? kmsan_get_shadow_origin_ptr+0x4d/0xb0
[  114.486658][    C0]  virtnet_poll+0xd1c/0x23c0
[  114.491392][    C0]  ? __pfx_virtnet_poll+0x10/0x10
[  114.496535][    C0]  __napi_poll+0xe7/0x980
[  114.500975][    C0]  ? kmsan_get_metadata+0x146/0x1d0
[  114.506376][    C0]  net_rx_action+0x82a/0x1850
[  114.511264][    C0]  ? sched_clock_cpu+0x55/0x870
[  114.516222][    C0]  ? __pfx_net_rx_action+0x10/0x10
[  114.521456][    C0]  handle_softirqs+0x1ce/0x800
[  114.526340][    C0]  __irq_exit_rcu+0x68/0x120
[  114.531117][    C0]  irq_exit_rcu+0x12/0x20
[  114.535538][    C0]  common_interrupt+0x94/0xa0
[  114.540324][    C0]  </IRQ>
[  114.543335][    C0]  <TASK>
[  114.546400][    C0]  asm_common_interrupt+0x2b/0x40
[  114.551563][    C0] RIP: 0010:acpi_safe_halt+0x25/0x30
[  114.557004][    C0] Code: 90 90 90 90 90 55 48 89 e5 65 48 8b 04 25 80 5e 0a 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d eb b8 44 00 f3 0f 1e fa fb f4 <fa> 5d c3 cc cc cc cc 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90
[  114.576730][    C0] RSP: 0018:ffffffff90e03ce8 EFLAGS: 00000246
[  114.582968][    C0] RAX: ffffffff90e2bdc0 RBX: ffffffff91286bb0 RCX: 0000000000000001
[  114.591022][    C0] RDX: ffff88810322e064 RSI: ffffffff91286bb0 RDI: ffff88810322e064
[  114.599114][    C0] RBP: ffffffff90e03ce8 R08: ffffea000000000f R09: 00000000000000ff
[  114.607295][    C0] R10: ffff88823f173dc2 R11: ffffffff8f78a590 R12: ffff888103ce3c00
[  114.615378][    C0] R13: ffffffff91286c30 R14: 0000000000000001 R15: 0000000000000001
[  114.623533][    C0]  ? __pfx_acpi_idle_enter+0x10/0x10
[  114.628953][    C0]  acpi_idle_do_entry+0x22/0x40
[  114.633915][    C0]  acpi_idle_enter+0xa1/0xc0
[  114.638600][    C0]  cpuidle_enter_state+0xcb/0x250
[  114.643752][    C0]  cpuidle_enter+0x7f/0xf0
[  114.648302][    C0]  do_idle+0x551/0x750
[  114.652474][    C0]  cpu_startup_entry+0x65/0x80
[  114.657345][    C0]  rest_init+0x1e8/0x260
[  114.661722][    C0]  start_kernel+0x92c/0xa70
[  114.666326][    C0]  x86_64_start_reservations+0x2e/0x30
[  114.671913][    C0]  x86_64_start_kernel+0x98/0xa0
[  114.676985][    C0]  common_startup_64+0x12c/0x137
[  114.682081][    C0]  </TASK>
[  114.685493][    C0] Kernel Offset: disabled
[  114.689884][    C0] 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-build3847290796=/tmp/go-build -gno-record-gcc-switches'

git status (err=<nil>)
HEAD detached at 53df08b6d9
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=53df08b6d9d1467aa178b49a550c7b722fd9aa42 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240408-113412'" "-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=53df08b6d9d1467aa178b49a550c7b722fd9aa42 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240408-113412'" "-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=53df08b6d9d1467aa178b49a550c7b722fd9aa42 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240408-113412'" "-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=\"53df08b6d9d1467aa178b49a550c7b722fd9aa42\"


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=159dd4fa980000


Tested on:

commit:         90302a82 kernel/bpf: KMSAN: uninit-value in htab_lru_p..
git tree:       https://linux.googlesource.com/linux/kernel/git/torvalds/linux
kernel config:  https://syzkaller.appspot.com/x/.config?x=b97faf4c225206cd
dashboard link: https://syzkaller.appspot.com/bug?extid=c33bff5d5da1391df027
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.