Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush

From: syzbot
Date: Wed Jul 24 2024 - 05:59:12 EST

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Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: stack-out-of-bounds Read in xdp_do_check_flushed

==================================================================
BUG: KASAN: stack-out-of-bounds in bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
BUG: KASAN: stack-out-of-bounds in xdp_do_check_flushed+0x41c/0x4e0 net/core/filter.c:4298
Read of size 4 at addr ffffc9000331fa50 by task syz.0.36/5802

CPU: 0 UID: 0 PID: 5802 Comm: syz.0.36 Not tainted 6.10.0-syzkaller-12246-g786c8248dbd3-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:93 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
bpf_net_ctx_get_all_used_flush_lists include/linux/filter.h:837 [inline]
xdp_do_check_flushed+0x41c/0x4e0 net/core/filter.c:4298
__napi_poll.constprop.0+0xd1/0x550 net/core/dev.c:6774
napi_poll net/core/dev.c:6840 [inline]
net_rx_action+0xa92/0x1010 net/core/dev.c:6962
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_call_function arch/x86/kernel/smp.c:257 [inline]
sysvec_call_function+0x95/0xb0 arch/x86/kernel/smp.c:257
</IRQ>
<TASK>
asm_sysvec_call_function+0x1a/0x20 arch/x86/include/asm/idtentry.h:710
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:200
Code: be b0 01 00 00 e8 a0 ff ff ff 31 c0 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 65 48 8b 15 94 54 79 7e 65 8b 05 95 54 79 7e a9 00 01
RSP: 0018:ffffc9000331f3e8 EFLAGS: 00000283
RAX: dffffc0000000000 RBX: ffffc9000331f470 RCX: ffffffff813cf026
RDX: 1ffff92000663e90 RSI: ffffffff813cf082 RDI: ffffc9000331f480
RBP: ffffc9000331fcd0 R08: 0000000000000004 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90003318000
R13: ffffc90003320000 R14: 0000000000000001 R15: 0000000000000001
on_stack arch/x86/include/asm/stacktrace.h:60 [inline]
unwind_next_frame+0x11af/0x23a0 arch/x86/kernel/unwind_orc.c:665
arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
__kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2252 [inline]
slab_free mm/slub.c:4473 [inline]
kmem_cache_free+0x12f/0x3a0 mm/slub.c:4548
anon_vma_chain_free mm/rmap.c:147 [inline]
unlink_anon_vmas+0x173/0x820 mm/rmap.c:421
free_pgtables+0x33c/0x950 mm/memory.c:409
exit_mmap+0x3c9/0xb20 mm/mmap.c:3393
__mmput+0x12a/0x480 kernel/fork.c:1345
mmput+0x62/0x70 kernel/fork.c:1367
exit_mm kernel/exit.c:571 [inline]
do_exit+0x9bf/0x2bb0 kernel/exit.c:869
do_group_exit+0xd3/0x2a0 kernel/exit.c:1031
get_signal+0x25fd/0x2770 kernel/signal.c:2917
arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0dd5175b59
Code: Unable to access opcode bytes at 0x7f0dd5175b2f.
RSP: 002b:00007f0dd5f6a0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f0dd5305f68 RCX: 00007f0dd5175b59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f0dd5305f68
RBP: 00007f0dd5305f60 R08: 00007f0dd5f6a6c0 R09: 00007f0dd5f6a6c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0dd5305f6c
R13: 000000000000000b R14: 00007ffd8748bdc0 R15: 00007ffd8748bea8
</TASK>

The buggy address belongs to stack of task syz.0.36/5802
and is located at offset 24 in frame:
exit_mmap+0x0/0xb20 mm/mmap.c:3202

This frame has 2 objects:
[32, 96) 'vmi'
[128, 256) 'tlb'

The buggy address belongs to the virtual mapping at
[ffffc90003318000, ffffc90003321000) created by:
kernel_clone+0xfd/0x980 kernel/fork.c:2781

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888029ce3690 pfn:0x29ce3
memcg:ffff88801dd09c02
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff888029ce3690 0000000000000000 00000001ffffffff ffff88801dd09c02
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 5781, tgid 5781 (syz.0.26), ts 125931643135, free_ts 125907940889
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1493
prep_new_page mm/page_alloc.c:1501 [inline]
get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3438
__alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4696
alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2263
vm_area_alloc_pages mm/vmalloc.c:3584 [inline]
__vmalloc_area_node mm/vmalloc.c:3660 [inline]
__vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3841
alloc_thread_stack_node kernel/fork.c:313 [inline]
dup_task_struct kernel/fork.c:1113 [inline]
copy_process+0x2f3b/0x8de0 kernel/fork.c:2204
kernel_clone+0xfd/0x980 kernel/fork.c:2781
__do_sys_clone3+0x1f5/0x270 kernel/fork.c:3085
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5780 tgid 5779 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1094 [inline]
free_unref_page+0x64a/0xe40 mm/page_alloc.c:2608
__folio_put+0x31c/0x3e0 mm/swap.c:128
folio_put include/linux/mm.h:1479 [inline]
free_page_and_swap_cache+0x249/0x2c0 mm/swap_state.c:308
__tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
__tlb_remove_table_free mm/mmu_gather.c:227 [inline]
tlb_remove_table_rcu+0x89/0xe0 mm/mmu_gather.c:282
rcu_do_batch kernel/rcu/tree.c:2569 [inline]
rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2843
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Memory state around the buggy address:
ffffc9000331f900: 00 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00
ffffc9000331f980: 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00
>ffffc9000331fa00: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00
^
ffffc9000331fa80: 00 00 00 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00
ffffc9000331fb00: 00 00 00 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
0: be b0 01 00 00 mov $0x1b0,%esi
5: e8 a0 ff ff ff call 0xffffffaa
a: 31 c0 xor %eax,%eax
c: c3 ret
d: cc int3
e: cc int3
f: cc int3
10: cc int3
11: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
18: 00 00
1a: 90 nop
1b: 90 nop
1c: 90 nop
1d: 90 nop
1e: 90 nop
1f: 90 nop
20: 90 nop
21: 90 nop
22: 90 nop
23: 90 nop
24: 90 nop
25: 90 nop
26: 90 nop
27: 90 nop
28: 90 nop
29: 90 nop
* 2a: f3 0f 1e fa endbr64 <-- trapping instruction
2e: 65 48 8b 15 94 54 79 mov %gs:0x7e795494(%rip),%rdx # 0x7e7954ca
35: 7e
36: 65 8b 05 95 54 79 7e mov %gs:0x7e795495(%rip),%eax # 0x7e7954d2
3d: a9 .byte 0xa9
3e: 00 01 add %al,(%rcx)

Tested on:

commit: 786c8248 Merge tag 'perf-tools-fixes-for-v6.11-2024-07..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12e39145980000
kernel config: https://syzkaller.appspot.com/x/.config?x=47beaba1a1054668
dashboard link: https://syzkaller.appspot.com/bug?extid=44623300f057a28baf1e
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=138553b5980000

Next message: Eric Dumazet: "Re: [PATCH] net: Provide sysctl to tune local port range to IANA specification"
Previous message: syzbot: "[syzbot] [wireless?] KMSAN: uninit-value in cfg80211_inform_bss_frame_data"
Next in thread: syzbot: "Re: [syzbot] [bpf?] [net?] general protection fault in __dev_flush"
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