[syzbot] [bpf?] KMSAN: uninit-value in htab_lru_map_delete_elem

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    026e680b0a08 Merge tag 'pwm/for-6.9-rc3-fixes' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11b1fee3180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5112b3f484393436
dashboard link: https://syzkaller.appspot.com/bug?extid=d40ad71c1ba64324d256
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=10b539b1180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13e55795180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3b5659d2008c/disk-026e680b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7fd1552fafde/vmlinux-026e680b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ba622b1b0ec4/bzImage-026e680b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d40ad71c1ba64324d256@xxxxxxxxxxxxxxxxxxxxxxxxx

=====================================================
BUG: KMSAN: uninit-value in htab_lock_bucket kernel/bpf/hashtab.c:160 [inline]
BUG: KMSAN: uninit-value in htab_lru_map_delete_elem+0x628/0xb20 kernel/bpf/hashtab.c:1459
 htab_lock_bucket kernel/bpf/hashtab.c:160 [inline]
 htab_lru_map_delete_elem+0x628/0xb20 kernel/bpf/hashtab.c:1459
 ____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_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
 kvfree+0x69/0x80 mm/util.c:680
 __bpf_prog_put_rcu+0x37/0xf0 kernel/bpf/syscall.c:2232
 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
 smap_restore arch/x86/include/asm/smap.h:56 [inline]
 get_shadow_origin_ptr mm/kmsan/instrumentation.c:37 [inline]
 __msan_metadata_ptr_for_load_8+0x2c/0x40 mm/kmsan/instrumentation.c:92
 last_frame arch/x86/kernel/unwind_frame.c:82 [inline]
 is_last_frame arch/x86/kernel/unwind_frame.c:87 [inline]
 is_last_task_frame+0x62/0x420 arch/x86/kernel/unwind_frame.c:156
 unwind_next_frame+0x9d/0x470 arch/x86/kernel/unwind_frame.c:276
 arch_stack_walk+0x1ec/0x2d0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xaa/0xe0 kernel/stacktrace.c:122
 kmsan_save_stack_with_flags mm/kmsan/core.c:74 [inline]
 kmsan_internal_chain_origin+0x57/0xd0 mm/kmsan/core.c:183
 __msan_chain_origin+0xc3/0x150 mm/kmsan/instrumentation.c:251
 __skb_dst_copy include/net/dst.h:282 [inline]
 skb_dst_copy include/net/dst.h:290 [inline]
 __copy_skb_header+0x362/0x850 net/core/skbuff.c:1528
 __skb_clone+0x57/0x650 net/core/skbuff.c:1579
 skb_clone+0x3aa/0x550 net/core/skbuff.c:2070
 __tcp_transmit_skb+0x438/0x4890 net/ipv4/tcp_output.c:1308
 tcp_transmit_skb net/ipv4/tcp_output.c:1480 [inline]
 tcp_write_xmit+0x3ee1/0x8900 net/ipv4/tcp_output.c:2792
 __tcp_push_pending_frames+0xc4/0x380 net/ipv4/tcp_output.c:2977
 tcp_push+0x755/0x7a0 net/ipv4/tcp.c:738
 tcp_sendmsg_locked+0x6079/0x6cb0 net/ipv4/tcp.c:1310
 tcp_sendmsg+0x49/0x90 net/ipv4/tcp.c:1342
 inet_sendmsg+0x142/0x280 net/ipv4/af_inet.c:851
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x267/0x380 net/socket.c:745
 sock_write_iter+0x368/0x3d0 net/socket.c:1160
 call_write_iter include/linux/fs.h:2108 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xb63/0x1520 fs/read_write.c:590
 ksys_write+0x20f/0x4c0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:652
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x72/0x7a

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: 1 PID: 5008 Comm: sshd Not tainted 6.9.0-rc2-syzkaller-00002-g026e680b0a08 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
=====================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup