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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fec50db7033e Linux 6.9-rc3
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1425a483180000
kernel config: https://syzkaller.appspot.com/x/.config?x=13e7da432565d94c
dashboard link: https://syzkaller.appspot.com/bug?extid=c33bff5d5da1391df027
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17b653d3180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=159a2cf3180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/901017b36ccc/disk-fec50db7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/16bfcf5618d3/vmlinux-fec50db7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dc9c5a1e7d02/bzImage-fec50db7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c33bff...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in spin_lock_bh include/linux/spinlock.h:356 [inline]
BUG: KMSAN: uninit-value in sock_hash_delete_elem+0x239/0x710 net/core/sock_map.c:945
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0x239/0x710 net/core/sock_map.c:945
____bpf_map_delete_elem kernel/bpf/helpers.c:77 [inline]
bpf_map_delete_elem+0x5c/0x80 kernel/bpf/helpers.c:73
___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
__bpf_prog_run32+0xb2/0xe0 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run3+0x132/0x320 kernel/trace/bpf_trace.c:2421
__bpf_trace_block_bio_remap+0x34/0x50 include/trace/events/block.h:507
__traceiter_block_bio_remap+0xa5/0x160 include/trace/events/block.h:507
trace_block_bio_remap include/trace/events/block.h:507 [inline]
blk_partition_remap block/blk-core.c:571 [inline]
submit_bio_noacct+0x2449/0x2800 block/blk-core.c:762
submit_bio+0x58a/0x5b0 block/blk-core.c:879
ext4_io_submit fs/ext4/page-io.c:378 [inline]
io_submit_add_bh fs/ext4/page-io.c:419 [inline]
ext4_bio_write_folio+0x1e76/0x2e40 fs/ext4/page-io.c:563
mpage_submit_folio+0x351/0x4a0 fs/ext4/inode.c:1869
mpage_map_and_submit_buffers fs/ext4/inode.c:2115 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2254 [inline]
ext4_do_writepages+0x3733/0x62e0 fs/ext4/inode.c:2679
ext4_writepages+0x312/0x830 fs/ext4/inode.c:2768
do_writepages+0x427/0xc30 mm/page-writeback.c:2612
__writeback_single_inode+0x10d/0x12c0 fs/fs-writeback.c:1650
writeback_sb_inodes+0xb48/0x1be0 fs/fs-writeback.c:1941
__writeback_inodes_wb+0x14c/0x440 fs/fs-writeback.c:2012
wb_writeback+0x4da/0xdf0 fs/fs-writeback.c:2119
wb_check_old_data_flush fs/fs-writeback.c:2223 [inline]
wb_do_writeback fs/fs-writeback.c:2276 [inline]
wb_workfn+0x110c/0x1940 fs/fs-writeback.c:2304
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa81/0x1bd0 kernel/workqueue.c:3335
worker_thread+0xea5/0x1560 kernel/workqueue.c:3416
kthread+0x3e2/0x540 kernel/kthread.c:388
ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

Local variable stack created at:
__bpf_prog_run32+0x43/0xe0 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run3+0x132/0x320 kernel/trace/bpf_trace.c:2421

CPU: 1 PID: 76 Comm: kworker/u8:5 Not tainted 6.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: writeback wb_workfn (flush-8:0)
=====================================================


---
This report is generated by a bot. It may contain errors.
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If the report is already addressed, let syzbot know by replying with:
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If you want syzbot to run the reproducer, reply with:
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#syz undup

[syzbot]

For archival purposes, forwarding an incoming command email to
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***

Subject: [PATCH] [syzbot] [bpf?] [net?] KMSAN: uninit-value in sock_hash_delete_elem
Author: wojciech...@infogain.com

#syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux e478cf26c556e4ab572ab0ab2306c986901dcd61

Some syzkaller repros create BPF code that passes as an argument to map
functions a pointer to uninitialized map key on bpf program stack. So far
handling calls to map functions did not check for not/initialized
pointed to values with some comments that it was not possible to tell the
pointer use be read or write op. This led to KMSAN report in a case of
reading not initialized map key.
The fix assumes ARG_PTR_TO_MAP_KEY arguments to map function calls from
BPF byte code are always of read type. For read access the value pointed
to by map key pointer is expected to be initialized. Otherwise the BPF
bytecode will not load.

Syzbot report

=====================================================
BUG: KMSAN: uninit-value in __htab_map_lookup_elem kernel/bpf/hashtab.c:691 [inline]
BUG: KMSAN: uninit-value in htab_lru_percpu_map_lookup_percpu_elem+0x3f8/0x630 kernel/bpf/hashtab.c:2343
__htab_map_lookup_elem kernel/bpf/hashtab.c:691 [inline]
htab_lru_percpu_map_lookup_percpu_elem+0x3f8/0x630 kernel/bpf/hashtab.c:2343
____bpf_map_lookup_percpu_elem kernel/bpf/helpers.c:133 [inline]
bpf_map_lookup_percpu_elem+0x67/0x90 kernel/bpf/helpers.c:130

___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
__bpf_prog_run32+0xb2/0xe0 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]

bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420
__bpf_trace_kfree+0x29/0x40 include/trace/events/kmem.h:94
trace_kfree include/trace/events/kmem.h:94 [inline]
kfree+0x6a5/0xa30 mm/slub.c:4377
security_task_free+0x115/0x150 security/security.c:3032
__put_task_struct+0x17f/0x730 kernel/fork.c:976
put_task_struct include/linux/sched/task.h:138 [inline]
delayed_put_task_struct+0x8a/0x280 kernel/exit.c:229
rcu_do_batch kernel/rcu/tree.c:2196 [inline]
rcu_core+0xa59/0x1e70 kernel/rcu/tree.c:2471
rcu_core_si+0x12/0x20 kernel/rcu/tree.c:2488
__do_softirq+0x1c0/0x7d7 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:633 [inline]
irq_exit_rcu+0x6a/0x130 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x83/0x90 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1f/0x30 arch/x86/include/asm/idtentry.h:702
__msan_metadata_ptr_for_load_8+0x31/0x40 mm/kmsan/instrumentation.c:92
filter_irq_stacks+0x60/0x1a0 kernel/stacktrace.c:397
stack_depot_save_flags+0x2c/0x6e0 lib/stackdepot.c:609
stack_depot_save+0x12/0x20 lib/stackdepot.c:685
__msan_poison_alloca+0x106/0x1b0 mm/kmsan/instrumentation.c:285
arch_local_save_flags arch/x86/include/asm/irqflags.h:67 [inline]
arch_local_irq_save arch/x86/include/asm/irqflags.h:103 [inline]
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
_raw_spin_lock_irqsave+0x35/0xc0 kernel/locking/spinlock.c:162
remove_wait_queue+0x36/0x270 kernel/sched/wait.c:54
do_wait+0x34a/0x530 kernel/exit.c:1640
kernel_wait4+0x2ab/0x480 kernel/exit.c:1790
__do_sys_wait4 kernel/exit.c:1818 [inline]
__se_sys_wait4 kernel/exit.c:1814 [inline]
__x64_sys_wait4+0x14e/0x310 kernel/exit.c:1814
x64_sys_call+0x6e6/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:62
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable stack created at:
__bpf_prog_run32+0x43/0xe0 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]

bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420

CPU: 0 PID: 5018 Comm: strace-static-x Not tainted 6.9.0-rc3-syzkaller-00355-g7efd0a74039f #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024

=====================================================
Signed-off-by: Wojciech Gładysz <wojciech...@infogain.com>
---
kernel/bpf/verifier.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 36ef8e96787e..13a9c2e2908a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7146,8 +7146,8 @@ static int check_stack_range_initialized(
* reads. However, if raw_mode is not set, we'll do extra
* checks below.
*/
- bounds_check_type = BPF_WRITE;
- clobber = true;
+ clobber = !meta || meta->raw_mode;
+ bounds_check_type = clobber ? BPF_WRITE : BPF_READ;
} else {
bounds_check_type = BPF_READ;
}
@@ -7230,8 +7230,7 @@ static int check_stack_range_initialized(
stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
if (*stype == STACK_MISC)
goto mark;
- if ((*stype == STACK_ZERO) ||
- (*stype == STACK_INVALID && env->allow_uninit_stack)) {
+ if (*stype == STACK_ZERO) {
if (clobber) {
/* helper can write anything into the stack */
*stype = STACK_MISC;
@@ -8748,6 +8747,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
meta->map_uid = reg->map_uid;
break;
case ARG_PTR_TO_MAP_KEY:
+ /* always mark read access */
+ meta->raw_mode = false;
/* bpf_map_xxx(..., map_ptr, ..., key) call:
* check that [key, key + map->key_size) are within
* stack limits and initialized
@@ -8763,7 +8764,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
}
err = check_helper_mem_access(env, regno,
meta->map_ptr->key_size, false,
- NULL);
+ meta);
break;
case ARG_PTR_TO_MAP_VALUE:
if (type_may_be_null(arg_type) && register_is_null(reg))
--
2.35.3

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: [PATCH] [syzbot] [bpf?] [net?] KMSAN: uninit-value in sock_hash_delete_elem
Author: wojciech...@infogain.com

#syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux 90302a82de094e0a51a2f51935ce27c4f1fe8dc4

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+c33bff...@syzkaller.appspotmail.com

Tested on:

commit: e478cf26 Merge branch 'bpf-fix-a-couple-of-test-failur..
git tree: https://linux.googlesource.com/linux/kernel/git/torvalds/linux
console output: https://syzkaller.appspot.com/x/log.txt?x=140ab12e980000
kernel config: https://syzkaller.appspot.com/x/.config?x=e2599baf258ef795

dashboard link: https://syzkaller.appspot.com/bug?extid=c33bff5d5da1391df027
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=168670b6980000

Note: testing is done by a robot and is best-effort only.

[syzbot]

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.

[syzbot]

> #syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux 0daa6e5ed1ccdeb65e07d4884961a8bb288a0f54
> #syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux
> The information in this email is confidential and may be legally privileged. It is intended solely for the addressee and access to it by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken based on it, is strictly prohibited and may be unlawful.

Command #2:
want either no args or 2 args (repo, branch), got 59

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: KMSAN: uninit-value in sock_hash_delete_elem
Author: wojciech...@infogain.com

#syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux 0daa6e5ed1ccdeb65e07d4884961a8bb288a0f54

[syzbot]

> #syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux

want either no args or 2 args (repo, branch), got 59

[syzbot]

Hello,

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

failed to checkout kernel repo https://linux.googlesource.com/linux/kernel/git/torvalds/linux on commit 0daa6e5ed1ccdeb65e07d4884961a8bb288a0f54: failed to run ["git" "checkout" "0daa6e5ed1ccdeb65e07d4884961a8bb288a0f54"]: exit status 128
fatal: Cannot switch branch to a non-commit '0daa6e5ed1ccdeb65e07d4884961a8bb288a0f54'



Tested on:

commit: [unknown
git tree: https://linux.googlesource.com/linux/kernel/git/torvalds/linux 0daa6e5ed1ccdeb65e07d4884961a8bb288a0f54
kernel config: https://syzkaller.appspot.com/x/.config?x=13e7da432565d94c

dashboard link: https://syzkaller.appspot.com/bug?extid=c33bff5d5da1391df027
compiler:

[syzbot]

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: KMSAN: uninit-value in sock_hash_delete_elem
Author: wojciech...@infogain.com

#syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux e478cf26c556e4ab572ab0ab2306c986901dcd61

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in sock_hash_delete_elem

=====================================================
BUG: KMSAN: uninit-value in spin_lock_bh include/linux/spinlock.h:356 [inline]
BUG: KMSAN: uninit-value in sock_hash_delete_elem+0x490/0x690 net/core/sock_map.c:939
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0x490/0x690 net/core/sock_map.c:939

____bpf_map_delete_elem kernel/bpf/helpers.c:77 [inline]
bpf_map_delete_elem+0x5c/0x80 kernel/bpf/helpers.c:73

___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:2011
__bpf_prog_run32+0xb2/0xe0 kernel/bpf/core.c:2250
bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline]
__bpf_prog_run include/linux/filter.h:667 [inline]
bpf_prog_run include/linux/filter.h:674 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2396 [inline]
bpf_trace_run3+0x201/0x500 kernel/trace/bpf_trace.c:2438
__bpf_trace_block_bio_remap+0x34/0x50 include/trace/events/block.h:507

trace_block_bio_remap include/trace/events/block.h:507 [inline]
blk_partition_remap block/blk-core.c:571 [inline]
submit_bio_noacct+0x2449/0x2800 block/blk-core.c:762
submit_bio+0x58a/0x5b0 block/blk-core.c:879

submit_bh_wbc+0x81e/0x890 fs/buffer.c:2804
submit_bh fs/buffer.c:2809 [inline]
write_dirty_buffer+0x1ac/0x1f0 fs/buffer.c:2822
flush_descriptor fs/jbd2/revoke.c:657 [inline]
jbd2_journal_write_revoke_records+0x1c0b/0x1c80 fs/jbd2/revoke.c:562
jbd2_journal_commit_transaction+0x1949/0xa620 fs/jbd2/commit.c:551
kjournald2+0x494/0x900 fs/jbd2/journal.c:201

kthread+0x3e2/0x540 kernel/kthread.c:388
ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

Local variable stack created at:

__bpf_prog_run32+0x43/0xe0 kernel/bpf/core.c:2250
bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline]
__bpf_prog_run include/linux/filter.h:667 [inline]
bpf_prog_run include/linux/filter.h:674 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2396 [inline]
bpf_trace_run3+0x201/0x500 kernel/trace/bpf_trace.c:2438

CPU: 0 PID: 4418 Comm: jbd2/sda1-8 Not tainted 6.9.0-rc1-syzkaller-00257-ge478cf26c556 #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024

=====================================================

Tested on:

commit: e478cf26 Merge branch 'bpf-fix-a-couple-of-test-failur..
git tree: https://linux.googlesource.com/linux/kernel/git/torvalds/linux

console output: https://syzkaller.appspot.com/x/log.txt?x=1663af02980000
kernel config: https://syzkaller.appspot.com/x/.config?x=e2599baf258ef795
dashboard link: https://syzkaller.appspot.com/bug?extid=c33bff5d5da1391df027

compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: [PATCH] kernel/bpf: enable BPF bytecode call parsing for uninit value

Author: wojciech...@infogain.com

#syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux e478cf26c556e4ab572ab0ab2306c986901dcd61

Some syzkaller repros create BPF code that passes as an argument to map
functions a pointer to uninitialized map key on bpf program stack. So far
handling calls to map functions did not check for not/initialized
pointed to values with some comments that it was not possible to tell the
pointer use be read or write op. This led to KMSAN report in a case of
reading not initialized map key.
The fix assumes ARG_PTR_TO_MAP_KEY arguments to map function calls from
BPF byte code are always of read type. For read access the value pointed
to by map key pointer is expected to be initialized. Otherwise the BPF
bytecode will not load.

You may want to add an STX line to your repro.c to init stack value
pointed to by R2 BPF register and adjust memcpy lenght:

memcpy((void*)0x20000458,
"\x00\x00\x00\x00\x00\x00\x00\x00" // ...
"\xb7\x08\x00\x00\x00\x00\x00\x00" // ALU64_MOV_K
"\x1f\x00\x00\x00\x00\x00\x00\x00" // SUB_X?
"\xbf\xa2\x00\x00\x00\x00\x00\x00" // ALU64_MOV_X
"\x07\x02\x00\x00\xf8\xff\xff\xff" // ALU(64)_ADD_{K,X}
"\x7a\x02\x00\x00\xef\xbe\xad\xde" // *** STX ***
"\xb7\x03\x00\x00\x00\x00\x00\x00" // ALU64_MOV_K
"\xb7\x04\x00\x00\x00\x00\x00\x00" // ALU64_MOV_K
"\x85\x00\x00\x00\xc3\x00\x00\x00" // CALL
"\x95", 73); // EXIT

Syzbot report

=====================================================

BUG: KMSAN: uninit-value in __htab_map_lookup_elem kernel/bpf/hashtab.c:691 [inline]
BUG: KMSAN: uninit-value in htab_lru_percpu_map_lookup_percpu_elem+0x3f8/0x630 kernel/bpf/hashtab.c:2343
__htab_map_lookup_elem kernel/bpf/hashtab.c:691 [inline]
htab_lru_percpu_map_lookup_percpu_elem+0x3f8/0x630 kernel/bpf/hashtab.c:2343
____bpf_map_lookup_percpu_elem kernel/bpf/helpers.c:133 [inline]
bpf_map_lookup_percpu_elem+0x67/0x90 kernel/bpf/helpers.c:130

___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
__bpf_prog_run32+0xb2/0xe0 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]

Local variable stack created at:
__bpf_prog_run32+0x43/0xe0 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]

bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420

CPU: 0 PID: 5018 Comm: strace-static-x Not tainted 6.9.0-rc3-syzkaller-00355-g7efd0a74039f #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024

=====================================================

Reported-by: syzbot+c33bff...@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c33bff5d5da1391df027
Link: https://lore.kernel.org/all/0000000000003b...@google.com/T/