On Mon, Nov 25, 2024 at 4:27 PM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> The issue is understood.
> Commit 3ddc2fefe6f3 ("mm: vmalloc: implement vrealloc()") is buggy.
>
#syz fix: mm: fix vrealloc()'s KASAN poisoning logic
> Fix is wip.
>
> Same as the other syzbot report.
>
> On Sun, Nov 24, 2024 at 6:50 PM syzbot
> <syzbot+7d9959e6503e8ffc8558@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: ac24e26aa08f Add linux-next specific files for 20241120
> > git tree: linux-next
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=14d91b78580000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=45719eec4c74e6ba
> > dashboard link: https://syzkaller.appspot.com/bug?extid=7d9959e6503e8ffc8558
> > 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=124d8ec0580000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1425a75f980000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/9c6bcf3605c7/disk-ac24e26a.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/4ce96eb398a9/vmlinux-ac24e26a.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/9a22aac22c90/bzImage-ac24e26a.xz
> >
> > The issue was bisected to:
> >
> > commit 96a30e469ca1d2b8cc7811b40911f8614b558241
> > Author: Andrii Nakryiko <andrii@xxxxxxxxxx>
> > Date: Fri Nov 15 00:13:03 2024 +0000
> >
> > bpf: use common instruction history across all states
> >
> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102bd930580000
> > final oops: https://syzkaller.appspot.com/x/report.txt?x=122bd930580000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=142bd930580000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+7d9959e6503e8ffc8558@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Fixes: 96a30e469ca1 ("bpf: use common instruction history across all states")
> >
> > ==================================================================
> > BUG: KASAN: vmalloc-out-of-bounds in vrealloc_noprof+0x340/0x3a0 mm/vmalloc.c:4095
> > Write of size 2097120 at addr ffffc90004c00020 by task syz-executor132/5834
> >
> > CPU: 1 UID: 0 PID: 5834 Comm: syz-executor132 Not tainted 6.12.0-next-20241120-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
> > Call Trace:
> > <TASK>
> > __dump_stack lib/dump_stack.c:94 [inline]
> > dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> > print_address_description mm/kasan/report.c:378 [inline]
> > print_report+0x169/0x550 mm/kasan/report.c:489
> > kasan_report+0x143/0x180 mm/kasan/report.c:602
> > kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
> > __asan_memset+0x23/0x50 mm/kasan/shadow.c:84
> > vrealloc_noprof+0x340/0x3a0 mm/vmalloc.c:4095
> > push_insn_history+0x16c/0x6a0 kernel/bpf/verifier.c:3571
> > check_mem_access+0xf30/0x2240 kernel/bpf/verifier.c:7267
> > do_check+0x7d97/0xfcd0 kernel/bpf/verifier.c:18703
> > do_check_common+0x1564/0x2010 kernel/bpf/verifier.c:21848
> > do_check_main kernel/bpf/verifier.c:21939 [inline]
> > bpf_check+0x19380/0x1f1b0 kernel/bpf/verifier.c:22656
> > bpf_prog_load+0x1667/0x20f0 kernel/bpf/syscall.c:2947
> > __sys_bpf+0x4ee/0x810 kernel/bpf/syscall.c:5790
> > __do_sys_bpf kernel/bpf/syscall.c:5897 [inline]
> > __se_sys_bpf kernel/bpf/syscall.c:5895 [inline]
> > __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5895
> > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> > entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > RIP: 0033:0x7fae10fcf269
> > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007ffdf2bc3148 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fae10fcf269
> > RDX: 0000000000000090 RSI: 0000000020000840 RDI: 0000000000000005
> > RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000000a0
> > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> > </TASK>
> >
> > The buggy address belongs to the virtual mapping at
> > [ffffc90004800000, ffffc90004e01000) created by:
> > kvrealloc_noprof+0xc7/0x120 mm/util.c:747
> >
> > The buggy address belongs to the physical page:
> > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6c600
> > flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
> > raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
> > raw: 0000000000000000 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 5834, tgid 5834 (syz-executor132), ts 114573563417, free_ts 25588986996
> > set_page_owner include/linux/page_owner.h:32 [inline]
> > post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
> > prep_new_page mm/page_alloc.c:1564 [inline]
> > get_page_from_freelist+0x3725/0x3870 mm/page_alloc.c:3510
> > __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4787
> > alloc_pages_mpol_noprof+0x3e8/0x680 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+0x9c9/0x1380 mm/vmalloc.c:3844
> > __kvmalloc_node_noprof+0x142/0x190 mm/util.c:672
> > kvrealloc_noprof+0xc7/0x120 mm/util.c:747
> > push_insn_history+0x16c/0x6a0 kernel/bpf/verifier.c:3571
> > check_mem_access+0xf30/0x2240 kernel/bpf/verifier.c:7267
> > do_check+0x7d97/0xfcd0 kernel/bpf/verifier.c:18703
> > do_check_common+0x1564/0x2010 kernel/bpf/verifier.c:21848
> > do_check_main kernel/bpf/verifier.c:21939 [inline]
> > bpf_check+0x19380/0x1f1b0 kernel/bpf/verifier.c:22656
> > bpf_prog_load+0x1667/0x20f0 kernel/bpf/syscall.c:2947
> > __sys_bpf+0x4ee/0x810 kernel/bpf/syscall.c:5790
> > __do_sys_bpf kernel/bpf/syscall.c:5897 [inline]
> > __se_sys_bpf kernel/bpf/syscall.c:5895 [inline]
> > __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5895
> > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> > page last free pid 1 tgid 1 stack trace:
> > reset_page_owner include/linux/page_owner.h:25 [inline]
> > free_pages_prepare mm/page_alloc.c:1127 [inline]
> > free_unref_page+0xdf9/0x1140 mm/page_alloc.c:2693
> > free_contig_range+0x152/0x550 mm/page_alloc.c:6666
> > destroy_args+0x92/0x910 mm/debug_vm_pgtable.c:1017
> > debug_vm_pgtable+0x4be/0x550 mm/debug_vm_pgtable.c:1397
> > do_one_initcall+0x248/0x880 init/main.c:1266
> > do_initcall_level+0x157/0x210 init/main.c:1328
> > do_initcalls+0x3f/0x80 init/main.c:1344
> > kernel_init_freeable+0x435/0x5d0 init/main.c:1577
> > kernel_init+0x1d/0x2b0 init/main.c:1466
> > ret_from_fork+0x4b/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:
> > ffffc90004bfff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > ffffc90004bfff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > >ffffc90004c00000: 00 00 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> > ^
> > ffffc90004c00080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> > ffffc90004c00100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> > ==================================================================
> >
> >
> > ---
> > 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.
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> >
> > 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
