Messages in this thread |  | | Date | Fri, 5 Jan 2024 18:16:18 +0100 | | Subject | Re: [syzbot] [mm?] WARNING in __folio_rmap_sanity_checks | | From | David Hildenbrand <> |
| |
On 05.01.24 18:04, Andrew Morton wrote: > (cc netdev) > > On Wed, 3 Jan 2024 22:16:13 +0800 "Yin, Fengwei" <fengwei.yin@intel.com> wrote: > >> >> >> On 1/3/2024 8:13 PM, David Hildenbrand wrote: >>> On 03.01.24 12:48, syzbot wrote: >>>> Hello, >>>> >>>> syzbot found the following issue on: >>>> >>>> HEAD commit: ab0b3e6ef50d Add linux-next specific files for 20240102 >>>> git tree: linux-next >>>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=17be3e09e80000 >>>> kernel config: >>>> https://syzkaller.appspot.com/x/.config?x=a14a6350374945f9 >>>> dashboard link: >>>> https://syzkaller.appspot.com/bug?extid=50ef73537bbc393a25bb >>>> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils >>>> for Debian) 2.40 >>>> syz repro: >>>> https://syzkaller.appspot.com/x/repro.syz?x=14e2256ee80000 >>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17b57db5e80000 >>>> >>>> Downloadable assets: >>>> disk image: >>>> https://storage.googleapis.com/syzbot-assets/4e6376fe5764/disk-ab0b3e6e.raw.xz >>>> vmlinux: >>>> https://storage.googleapis.com/syzbot-assets/7cb9ecbaf001/vmlinux-ab0b3e6e.xz >>>> kernel image: >>>> https://storage.googleapis.com/syzbot-assets/2c1a9a6d424f/bzImage-ab0b3e6e.xz >>>> >>>> The issue was bisected to: >>>> >>>> commit 68f0320824fa59c5429cbc811e6c46e7a30ea32c >>>> Author: David Hildenbrand <david@redhat.com> >>>> Date: Wed Dec 20 22:44:31 2023 +0000 >>>> >>>> mm/rmap: convert folio_add_file_rmap_range() into >>>> folio_add_file_rmap_[pte|ptes|pmd]() >>>> >>>> bisection log: >>>> https://syzkaller.appspot.com/x/bisect.txt?x=10b9e1b1e80000 >>>> final oops: >>>> https://syzkaller.appspot.com/x/report.txt?x=12b9e1b1e80000 >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=14b9e1b1e80000 >>>> >>>> IMPORTANT: if you fix the issue, please add the following tag to the >>>> commit: >>>> Reported-by: syzbot+50ef73537bbc393a25bb@syzkaller.appspotmail.com >>>> Fixes: 68f0320824fa ("mm/rmap: convert folio_add_file_rmap_range() >>>> into folio_add_file_rmap_[pte|ptes|pmd]()") >>>> >>>> kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:283 >>>> __kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:324 >>>> kasan_slab_alloc include/linux/kasan.h:201 [inline] >>>> slab_post_alloc_hook mm/slub.c:3813 [inline] >>>> slab_alloc_node mm/slub.c:3860 [inline] >>>> kmem_cache_alloc+0x136/0x320 mm/slub.c:3867 >>>> vm_area_alloc+0x1f/0x220 kernel/fork.c:465 >>>> mmap_region+0x3ae/0x2a90 mm/mmap.c:2804 >>>> do_mmap+0x890/0xef0 mm/mmap.c:1379 >>>> vm_mmap_pgoff+0x1a7/0x3c0 mm/util.c:573 >>>> ksys_mmap_pgoff+0x421/0x5a0 mm/mmap.c:1425 >>>> __do_sys_mmap arch/x86/kernel/sys_x86_64.c:93 [inline] >>>> __se_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline] >>>> __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:86 >>>> do_syscall_x64 arch/x86/entry/common.c:52 [inline] >>>> do_syscall_64+0xd0/0x250 arch/x86/entry/common.c:83 >>>> entry_SYSCALL_64_after_hwframe+0x62/0x6a >>>> ------------[ cut here ]------------ >>>> WARNING: CPU: 1 PID: 5059 at include/linux/rmap.h:202 >>>> __folio_rmap_sanity_checks+0x4d5/0x630 include/linux/rmap.h:202 >>>> Modules linked in: >>>> CPU: 1 PID: 5059 Comm: syz-executor115 Not tainted >>>> 6.7.0-rc8-next-20240102-syzkaller #0 >>>> Hardware name: Google Google Compute Engine/Google Compute Engine, >>>> BIOS Google 11/17/2023 >>>> RIP: 0010:__folio_rmap_sanity_checks+0x4d5/0x630 include/linux/rmap.h:202 >>>> Code: 41 83 e4 01 44 89 e6 e8 79 bc b7 ff 45 84 e4 0f 85 08 fc ff ff >>>> e8 3b c1 b7 ff 48 c7 c6 e0 b5 d9 8a 48 89 df e8 5c 12 f7 ff 90 <0f> 0b >>>> 90 e9 eb fb ff ff e8 1e c1 b7 ff be 01 00 00 00 48 89 df e8 >>>> RSP: 0018:ffffc900038df978 EFLAGS: 00010293 >>>> RAX: 0000000000000000 RBX: ffffea00008cde00 RCX: ffffffff81687419 >>>> RDX: ffff88807becbb80 RSI: ffffffff81d06104 RDI: 0000000000000000 >>>> RBP: ffffea00008cde00 R08: 0000000000000000 R09: fffffbfff1e75f6a >>>> R10: ffffffff8f3afb57 R11: 0000000000000001 R12: 0000000000000000 >>>> R13: 0000000000000001 R14: 0000000000000000 R15: dffffc0000000000 >>>> FS: 0000555556508380(0000) GS:ffff8880b9900000(0000) >>>> knlGS:0000000000000000 >>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>> CR2: 00000000200000c0 CR3: 0000000079000000 CR4: 00000000003506f0 >>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>>> Call Trace: >>>> <TASK> >>>> __folio_add_rmap mm/rmap.c:1167 [inline] >>>> __folio_add_file_rmap mm/rmap.c:1452 [inline] >>>> folio_add_file_rmap_ptes+0x8e/0x2c0 mm/rmap.c:1478 >>>> insert_page_into_pte_locked.isra.0+0x34d/0x960 mm/memory.c:1874 >>>> insert_page mm/memory.c:1900 [inline] >>>> vm_insert_page+0x62c/0x8c0 mm/memory.c:2053 >>>> packet_mmap+0x314/0x570 net/packet/af_packet.c:4594 >>>> call_mmap include/linux/fs.h:2090 [inline] >>>> mmap_region+0x745/0x2a90 mm/mmap.c:2819 >>>> do_mmap+0x890/0xef0 mm/mmap.c:1379 >>>> vm_mmap_pgoff+0x1a7/0x3c0 mm/util.c:573 >>>> ksys_mmap_pgoff+0x421/0x5a0 mm/mmap.c:1425 >>>> __do_sys_mmap arch/x86/kernel/sys_x86_64.c:93 [inline] >>>> __se_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline] >>>> __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:86 >>>> do_syscall_x64 arch/x86/entry/common.c:52 [inline] >>>> do_syscall_64+0xd0/0x250 arch/x86/entry/common.c:83 >>>> entry_SYSCALL_64_after_hwframe+0x62/0x6a >>> >>> If I am not wrong, that triggers: >>> >>> VM_WARN_ON_FOLIO(folio_test_large(folio) && >>> !folio_test_large_rmappable(folio), folio); >>> >>> So we are trying to rmap a large folio that did not go through >>> folio_prep_large_rmappable(). >>> >>> net/packet/af_packet.c calls vm_insert_page() on some pages/folios stoed >>> in the "struct packet_ring_buffer". No idea where that comes from, but I >>> suspect it's simply some compound allocation. >> Looks like: >> alloc_pg_vec >> alloc_one_pg_vec_page >> gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | >> __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY; >> >> buffer = (char *) __get_free_pages(gfp_flags, order); >> So you are right here... :). > > Can we suggest what af_packet should be doing to avoid this?
I concluded that af_packet is doing the right thing and we have to figure out how we want to handle that internally differently at some point.
I just shared a patch to revert that check for now, let me know if you want an "officially" sent patch :)
-- Cheers,
David / dhildenb
|  |