linux-kernel - [syzbot] [bpf?] KMSAN: uninit-value in htab_lru_percpu_map_lookup

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Message-ID: <0000000000002e2b130615707e3c@google.com>
Date: Sat, 06 Apr 2024 09:59:17 -0700
From: syzbot <syzbot+b8d77b9bb107fa1bd641@...kaller.appspotmail.com>
To: andrii@...nel.org, ast@...nel.org, bpf@...r.kernel.org, 
	daniel@...earbox.net, eddyz87@...il.com, haoluo@...gle.com, 
	john.fastabend@...il.com, jolsa@...nel.org, kpsingh@...nel.org, 
	linux-kernel@...r.kernel.org, martin.lau@...ux.dev, sdf@...gle.com, 
	song@...nel.org, syzkaller-bugs@...glegroups.com, yonghong.song@...ux.dev
Subject: [syzbot] [bpf?] KMSAN: uninit-value in htab_lru_percpu_map_lookup_elem

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=173c55e5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5112b3f484393436
dashboard link: https://syzkaller.appspot.com/bug?extid=b8d77b9bb107fa1bd641
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=1495512d180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=143c2415180000

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+b8d77b9bb107fa1bd641@...kaller.appspotmail.com

=====================================================
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_elem+0x39a/0x580 kernel/bpf/hashtab.c:2326
 __htab_map_lookup_elem kernel/bpf/hashtab.c:691 [inline]
 htab_lru_percpu_map_lookup_elem+0x39a/0x580 kernel/bpf/hashtab.c:2326
 ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
 bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
 __bpf_prog_run64+0xb5/0xe0 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
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:94 [inline]
 flush_tlb_mm_range+0x294/0x320 arch/x86/mm/tlb.c:1036
 flush_tlb_page arch/x86/include/asm/tlbflush.h:254 [inline]
 ptep_clear_flush+0x166/0x1c0 mm/pgtable-generic.c:101
 wp_page_copy mm/memory.c:3329 [inline]
 do_wp_page+0x419d/0x66e0 mm/memory.c:3660
 handle_pte_fault mm/memory.c:5316 [inline]
 __handle_mm_fault mm/memory.c:5441 [inline]
 handle_mm_fault+0x5b76/0xce00 mm/memory.c:5606
 do_user_addr_fault arch/x86/mm/fault.c:1362 [inline]
 handle_page_fault arch/x86/mm/fault.c:1505 [inline]
 exc_page_fault+0x419/0x730 arch/x86/mm/fault.c:1563
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623

Local variable stack created at:
 __bpf_prog_run64+0x45/0xe0 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: 5015 Comm: syz-executor232 Not tainted 6.9.0-rc2-syzkaller-00002-g026e680b0a08 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
=====================================================


---
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