The issue is understood.
Commit 3ddc2fefe6f3 ("mm: vmalloc: implement vrealloc()") is buggy.
Fix is wip.
On Mon, Nov 25, 2024 at 4:00 PM syzbot
<syzbot+5ca500b6e0bdb0d11dbc@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 9f16d5e6f220 Merge tag 'for-linus' of git://git.kernel.org..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11e13ee8580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=b193f152f0257905
> dashboard link: https://syzkaller.appspot.com/bug?extid=5ca500b6e0bdb0d11dbc
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-9f16d5e6.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/e4af736be07e/vmlinux-9f16d5e6.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/8b23128a7c9e/bzImage-9f16d5e6.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+5ca500b6e0bdb0d11dbc@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> ==================================================================
> BUG: KASAN: vmalloc-out-of-bounds in push_insn_history+0x615/0x690 kernel/bpf/verifier.c:3579
> Write of size 4 at addr ffffc90002db9010 by task syz.0.4094/25926
>
> CPU: 3 UID: 0 PID: 25926 Comm: syz.0.4094 Not tainted 6.12.0-syzkaller-09073-g9f16d5e6f220 #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:
> <TASK>
> __dump_stack lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
> print_address_description mm/kasan/report.c:378 [inline]
> print_report+0xc3/0x620 mm/kasan/report.c:489
> kasan_report+0xd9/0x110 mm/kasan/report.c:602
> push_insn_history+0x615/0x690 kernel/bpf/verifier.c:3579
> do_check kernel/bpf/verifier.c:18594 [inline]
> do_check_common+0xb78/0xd540 kernel/bpf/verifier.c:21848
> do_check_main kernel/bpf/verifier.c:21939 [inline]
> bpf_check+0x77c2/0xc9b0 kernel/bpf/verifier.c:22656
> bpf_prog_load+0xe3f/0x2670 kernel/bpf/syscall.c:2947
> __sys_bpf+0x5677/0x57a0 kernel/bpf/syscall.c:5790
> __do_sys_bpf kernel/bpf/syscall.c:5897 [inline]
> __se_sys_bpf kernel/bpf/syscall.c:5895 [inline]
> __ia32_sys_bpf+0x76/0xe0 kernel/bpf/syscall.c:5895
> do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
> __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
> do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
> RIP: 0023:0xf740e579
> Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
> RSP: 002b:00000000f50d555c EFLAGS: 00000296 ORIG_RAX: 0000000000000165
> RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00000000200017c0
> RDX: 0000000000000048 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> </TASK>
>
> The buggy address belongs to the virtual mapping at
> [ffffc90002d99000, ffffc90002dbb000) created by:
> kvrealloc_noprof+0xfc/0x150 mm/util.c:755
>
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880741c9e88 pfn:0x741c9
> flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
> raw: 04fff00000000000 0000000000000000 dead000000000122 0000000000000000
> raw: ffff8880741c9e88 0000000000000000 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102cc2(GFP_HIGHUSER|__GFP_NOWARN), pid 25926, tgid 25924 (syz.0.4094), ts 1129383943138, free_ts 1129046992178
> set_page_owner include/linux/page_owner.h:32 [inline]
> post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1556
> prep_new_page mm/page_alloc.c:1564 [inline]
> get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3474
> __alloc_pages_slowpath mm/page_alloc.c:4286 [inline]
> __alloc_pages_noprof+0x6a6/0x25a0 mm/page_alloc.c:4764
> alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
> vm_area_alloc_pages mm/vmalloc.c:3589 [inline]
> __vmalloc_area_node mm/vmalloc.c:3667 [inline]
> __vmalloc_node_range_noprof+0x724/0x1530 mm/vmalloc.c:3844
> __kvmalloc_node_noprof+0x14f/0x1a0 mm/util.c:680
> kvrealloc_noprof+0xfc/0x150 mm/util.c:755
> push_insn_history+0x2ac/0x690 kernel/bpf/verifier.c:3571
> do_check kernel/bpf/verifier.c:18594 [inline]
> do_check_common+0xb78/0xd540 kernel/bpf/verifier.c:21848
> do_check_main kernel/bpf/verifier.c:21939 [inline]
> bpf_check+0x77c2/0xc9b0 kernel/bpf/verifier.c:22656
> bpf_prog_load+0xe3f/0x2670 kernel/bpf/syscall.c:2947
> __sys_bpf+0x5677/0x57a0 kernel/bpf/syscall.c:5790
> __do_sys_bpf kernel/bpf/syscall.c:5897 [inline]
> __se_sys_bpf kernel/bpf/syscall.c:5895 [inline]
> __ia32_sys_bpf+0x76/0xe0 kernel/bpf/syscall.c:5895
> do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
> __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
> do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
> page last free pid 29 tgid 29 stack trace:
> reset_page_owner include/linux/page_owner.h:25 [inline]
> free_pages_prepare mm/page_alloc.c:1127 [inline]
> free_unref_page+0x661/0x1080 mm/page_alloc.c:2657
> rcu_do_batch kernel/rcu/tree.c:2567 [inline]
> rcu_core+0x79d/0x14d0 kernel/rcu/tree.c:2823
> handle_softirqs+0x213/0x8f0 kernel/softirq.c:554
> run_ksoftirqd kernel/softirq.c:943 [inline]
> run_ksoftirqd+0x3a/0x60 kernel/softirq.c:935
> smpboot_thread_fn+0x661/0xa30 kernel/smpboot.c:164
> kthread+0x2c1/0x3a0 kernel/kthread.c:389
> ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> Memory state around the buggy address:
> ffffc90002db8f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffffc90002db8f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffffc90002db9000: 00 00 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> ^
> ffffc90002db9080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> ffffc90002db9100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> ==================================================================
> ----------------
> Code disassembly (best guess), 2 bytes skipped:
> 0: 10 06 adc %al,(%rsi)
> 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
> 6: 10 07 adc %al,(%rdi)
> 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
> c: 10 08 adc %cl,(%rax)
> e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
> 1e: 00 51 52 add %dl,0x52(%rcx)
> 21: 55 push %rbp
> 22: 89 e5 mov %esp,%ebp
> 24: 0f 34 sysenter
> 26: cd 80 int $0x80
> * 28: 5d pop %rbp <-- trapping instruction
> 29: 5a pop %rdx
> 2a: 59 pop %rcx
> 2b: c3 ret
> 2c: 90 nop
> 2d: 90 nop
> 2e: 90 nop
> 2f: 90 nop
> 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
> 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
>
>
> ---
> 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 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
