> On Oct 17, 2024, at 4:34 AM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > On Sun, 22 Sept 2024 at 21:30, 'Chuck Lever III' via syzkaller-bugs > <syzkaller-bugs@xxxxxxxxxxxxxxxx> wrote: >> >> >> >>> On Sep 20, 2024, at 3:13 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: >>> >>> On Fri, 2024-09-20 at 18:51 +0000, Chuck Lever III wrote: >>>> >>>>> On Sep 19, 2024, at 10:57 PM, NeilBrown <neilb@xxxxxxx> wrote: >>>>> >>>>> On Thu, 19 Sep 2024, Jeff Layton wrote: >>>>>> On Wed, 2024-09-18 at 08:38 -0700, syzbot wrote: >>>>>>> Hello, >>>>>>> >>>>>>> syzbot found the following issue on: >>>>>>> >>>>>>> HEAD commit: a430d95c5efa Merge tag 'lsm-pr-20240911' of git://git.kern.. >>>>>>> git tree: upstream >>>>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=17c7469f980000 >>>>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=a69c66e868285a9d >>>>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=24cd636199753ac5e0ca >>>>>>> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 >>>>>>> >>>>>>> Unfortunately, I don't have any reproducer for this issue yet. >>>>>>> >>>>>>> Downloadable assets: >>>>>>> disk image: https://storage.googleapis.com/syzbot-assets/7f3aff905e91/disk-a430d95c.raw.xz >>>>>>> vmlinux: https://storage.googleapis.com/syzbot-assets/a468ce8431f0/vmlinux-a430d95c.xz >>>>>>> kernel image: https://storage.googleapis.com/syzbot-assets/80d4f1150155/bzImage-a430d95c.xz >>>>>>> >>>>>>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>>>>>> Reported-by: syzbot+24cd636199753ac5e0ca@xxxxxxxxxxxxxxxxxxxxxxxxx >>>>>>> >>>>>>> svc: failed to register nfsdv3 RPC service (errno 111). >>>>>>> svc: failed to register nfsaclv3 RPC service (errno 111). >>>>>>> ================================================================== >>>>>>> BUG: KASAN: slab-use-after-free in list_add include/linux/list.h:169 [inline] >>>>>>> BUG: KASAN: slab-use-after-free in rhashtable_walk_enter+0x333/0x370 lib/rhashtable.c:684 >>>>>>> Read of size 8 at addr ffff8880773fa010 by task syz.2.11924/9970 >>>>>>> >>>>>>> CPU: 0 UID: 0 PID: 9970 Comm: syz.2.11924 Not tainted 6.11.0-syzkaller-02574-ga430d95c5efa #0 >>>>>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 >>>>>>> Call Trace: >>>>>>> <TASK> >>>>>>> __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 >>>>>>> list_add include/linux/list.h:169 [inline] >>>>>>> rhashtable_walk_enter+0x333/0x370 lib/rhashtable.c:684 >>>>>>> rhltable_walk_enter include/linux/rhashtable.h:1262 [inline] >>>>>>> __nfsd_file_cache_purge+0xad/0x490 fs/nfsd/filecache.c:805 >>>>>>> nfsd_file_cache_shutdown+0xcf/0x480 fs/nfsd/filecache.c:897 >>>>>>> nfsd_shutdown_generic fs/nfsd/nfssvc.c:329 [inline] >>>>>>> nfsd_shutdown_generic fs/nfsd/nfssvc.c:323 [inline] >>>>>>> nfsd_startup_net fs/nfsd/nfssvc.c:444 [inline] >>>>>>> nfsd_svc+0x6d4/0x970 fs/nfsd/nfssvc.c:817 >>>>>>> nfsd_nl_threads_set_doit+0x52c/0xbc0 fs/nfsd/nfsctl.c:1714 >>>>>>> genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115 >>>>>>> genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] >>>>>>> genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210 >>>>>>> netlink_rcv_skb+0x165/0x410 net/netlink/af_netlink.c:2550 >>>>>>> genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 >>>>>>> netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] >>>>>>> netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1357 >>>>>>> netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1901 >>>>>>> sock_sendmsg_nosec net/socket.c:730 [inline] >>>>>>> __sock_sendmsg net/socket.c:745 [inline] >>>>>>> ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2603 >>>>>>> ___sys_sendmsg+0x135/0x1e0 net/socket.c:2657 >>>>>>> __sys_sendmsg+0x117/0x1f0 net/socket.c:2686 >>>>>>> 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 >>>>>>> RIP: 0033:0x7fd947f7def9 >>>>>>> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 >>>>>>> RSP: 002b:00007fd948e38038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e >>>>>>> RAX: ffffffffffffffda RBX: 00007fd948135f80 RCX: 00007fd947f7def9 >>>>>>> RDX: 0000000000000004 RSI: 0000000020000280 RDI: 0000000000000003 >>>>>>> RBP: 00007fd947ff0b76 R08: 0000000000000000 R09: 0000000000000000 >>>>>>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 >>>>>>> R13: 0000000000000000 R14: 00007fd948135f80 R15: 00007ffc6cab9d78 >>>>>>> </TASK> >>>>>>> >>>>>>> Allocated by task 8716: >>>>>>> kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 >>>>>>> kasan_save_track+0x14/0x30 mm/kasan/common.c:68 >>>>>>> poison_kmalloc_redzone mm/kasan/common.c:370 [inline] >>>>>>> __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 >>>>>>> kasan_kmalloc include/linux/kasan.h:211 [inline] >>>>>>> __do_kmalloc_node mm/slub.c:4159 [inline] >>>>>>> __kmalloc_node_track_caller_noprof+0x20f/0x440 mm/slub.c:4178 >>>>>>> kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:609 >>>>>>> __alloc_skb+0x164/0x380 net/core/skbuff.c:678 >>>>>>> alloc_skb include/linux/skbuff.h:1322 [inline] >>>>>>> nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] >>>>>>> nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] >>>>>>> nsim_dev_trap_report_work+0x2a4/0xc80 drivers/net/netdevsim/dev.c:850 >>>>>>> process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231 >>>>>>> process_scheduled_works kernel/workqueue.c:3312 [inline] >>>>>>> worker_thread+0x6c8/0xf00 kernel/workqueue.c:3393 >>>>>>> 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 >>>>>>> >>>>>>> Freed by task 8716: >>>>>>> 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:2250 [inline] >>>>>>> slab_free mm/slub.c:4474 [inline] >>>>>>> kfree+0x12a/0x3b0 mm/slub.c:4595 >>>>>>> skb_kfree_head net/core/skbuff.c:1086 [inline] >>>>>>> skb_free_head+0x108/0x1d0 net/core/skbuff.c:1098 >>>>>>> skb_release_data+0x75d/0x990 net/core/skbuff.c:1125 >>>>>>> skb_release_all net/core/skbuff.c:1190 [inline] >>>>>>> __kfree_skb net/core/skbuff.c:1204 [inline] >>>>>>> consume_skb net/core/skbuff.c:1436 [inline] >>>>>>> consume_skb+0xbf/0x100 net/core/skbuff.c:1430 >>>>>>> nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline] >>>>>>> nsim_dev_trap_report_work+0x878/0xc80 drivers/net/netdevsim/dev.c:850 >>>>>>> process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231 >>>>>>> process_scheduled_works kernel/workqueue.c:3312 [inline] >>>>>>> worker_thread+0x6c8/0xf00 kernel/workqueue.c:3393 >>>>>>> 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 >>>>>>> >>>>>>> The buggy address belongs to the object at ffff8880773fa000 >>>>>>> which belongs to the cache kmalloc-4k of size 4096 >>>>>>> The buggy address is located 16 bytes inside of >>>>>>> freed 4096-byte region [ffff8880773fa000, ffff8880773fb000) >>>>>>> >>>>>>> The buggy address belongs to the physical page: >>>>>>> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x773f8 >>>>>>> head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 >>>>>>> flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) >>>>>>> page_type: 0xfdffffff(slab) >>>>>>> raw: 00fff00000000040 ffff88801ac42140 ffffea0001e63600 dead000000000002 >>>>>>> raw: 0000000000000000 0000000000040004 00000001fdffffff 0000000000000000 >>>>>>> head: 00fff00000000040 ffff88801ac42140 ffffea0001e63600 dead000000000002 >>>>>>> head: 0000000000000000 0000000000040004 00000001fdffffff 0000000000000000 >>>>>>> head: 00fff00000000003 ffffea0001dcfe01 ffffffffffffffff 0000000000000000 >>>>>>> head: 0000000700000008 0000000000000000 00000000ffffffff 0000000000000000 >>>>>>> page dumped because: kasan: bad access detected >>>>>>> page_owner tracks the page as allocated >>>>>>> page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5240, tgid 5240 (syz-executor), ts 74499202771, free_ts 74134964798 >>>>>>> set_page_owner include/linux/page_owner.h:32 [inline] >>>>>>> post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1500 >>>>>>> prep_new_page mm/page_alloc.c:1508 [inline] >>>>>>> get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3446 >>>>>>> __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4702 >>>>>>> __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] >>>>>>> alloc_pages_node_noprof include/linux/gfp.h:296 [inline] >>>>>>> alloc_slab_page+0x4e/0xf0 mm/slub.c:2319 >>>>>>> allocate_slab mm/slub.c:2482 [inline] >>>>>>> new_slab+0x84/0x260 mm/slub.c:2535 >>>>>>> ___slab_alloc+0xdac/0x1870 mm/slub.c:3721 >>>>>>> __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3811 >>>>>>> __slab_alloc_node mm/slub.c:3864 [inline] >>>>>>> slab_alloc_node mm/slub.c:4026 [inline] >>>>>>> __do_kmalloc_node mm/slub.c:4158 [inline] >>>>>>> __kmalloc_noprof+0x379/0x410 mm/slub.c:4171 >>>>>>> kmalloc_noprof include/linux/slab.h:694 [inline] >>>>>>> tomoyo_realpath_from_path+0xbf/0x710 security/tomoyo/realpath.c:251 >>>>>>> tomoyo_get_realpath security/tomoyo/file.c:151 [inline] >>>>>>> tomoyo_path_number_perm+0x245/0x5b0 security/tomoyo/file.c:723 >>>>>>> security_file_ioctl+0x9b/0x240 security/security.c:2908 >>>>>>> __do_sys_ioctl fs/ioctl.c:901 [inline] >>>>>>> __se_sys_ioctl fs/ioctl.c:893 [inline] >>>>>>> __x64_sys_ioctl+0xbb/0x210 fs/ioctl.c:893 >>>>>>> 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 5233 tgid 5233 stack trace: >>>>>>> reset_page_owner include/linux/page_owner.h:25 [inline] >>>>>>> free_pages_prepare mm/page_alloc.c:1101 [inline] >>>>>>> free_unref_folios+0x9e9/0x1390 mm/page_alloc.c:2667 >>>>>>> folios_put_refs+0x560/0x760 mm/swap.c:1039 >>>>>>> free_pages_and_swap_cache+0x36d/0x510 mm/swap_state.c:332 >>>>>>> __tlb_batch_free_encoded_pages+0xf9/0x290 mm/mmu_gather.c:136 >>>>>>> tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] >>>>>>> tlb_flush_mmu_free mm/mmu_gather.c:366 [inline] >>>>>>> tlb_flush_mmu mm/mmu_gather.c:373 [inline] >>>>>>> tlb_finish_mmu+0x168/0x7b0 mm/mmu_gather.c:465 >>>>>>> unmap_region+0x342/0x420 mm/mmap.c:2441 >>>>>>> do_vmi_align_munmap+0x1107/0x19c0 mm/mmap.c:2754 >>>>>>> do_vmi_munmap+0x231/0x410 mm/mmap.c:2830 >>>>>>> __vm_munmap+0x142/0x330 mm/mmap.c:3109 >>>>>>> __do_sys_munmap mm/mmap.c:3126 [inline] >>>>>>> __se_sys_munmap mm/mmap.c:3123 [inline] >>>>>>> __x64_sys_munmap+0x61/0x90 mm/mmap.c:3123 >>>>>>> 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 >>>>>>> >>>>>>> Memory state around the buggy address: >>>>>>> ffff8880773f9f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>>>>>> ffff8880773f9f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>>>>>>> ffff8880773fa000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>>>>> ^ >>>>>>> ffff8880773fa080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>>>>> ffff8880773fa100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>>>>> ================================================================== >>>>>>> >>>>>>> >>>>>>> --- >>>>>>> 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 >>>>>> >>>>>> So we're tearing down the server and cleaning out the nfsd_file hash, >>>>>> and we hit a UAF. That probably means that we freed a nfsd_file without >>>>>> removing it from the hash? Maybe we should add a WARN_ON() in >>>>>> nfsd_file_slab_free that checks whether the item is still hashed? >>>>>> >>>>>> It is strange though. struct nfsd_file is 112 bytes on my machine, but >>>>>> the warning is about a 4k allocation. I guess that just means that the >>>>>> page got recycled into a different slabcache. >>>>> >>>>> The code that is crashing hasn't come close to touching anything that is >>>>> thought to be an nfsd_file. >>>>> The error is detected in the list_add() in rhashtable_walk_enter() when >>>>> the new on-stack iterator is being attached to the bucket_table that is being >>>>> iterated. So that bucket_table must (now) be an invalid address. >>>>> >>>>> The handling of NFSD_FILE_CACHE_UP is strange. nfsd_file_cache_init() >>>>> sets it, but doesn't clear it on failure. So if nfsd_file_cache_init() >>>>> fails for some reason, nfsd_file_cache_shutdown() would still try to >>>>> clean up if it was called. >>>>> >>>>> So suppose nfsd_startup_generic() is called. It increments nfsd_users >>>>> from 0 so continues to nfsd_file_cache_init() which fails for some >>>>> reason after initialising nfsd_file_rhltable and then destroying it. >>>>> This will leave nfsd_file_rhltable.tbl as a pointer to a large >>>>> allocation which has been freed. nfsd_startup_generic() will then >>>>> decrement nfsd_users back to zero, but NFSD_FILE_CACHE_UP will still be >>>>> set. >>>>> >>>>> When nfsd_startup_generic() is called again, nfsd_file_cache_init() will >>>>> skip initialisation because NFSD_FILE_CACHE_UP is set. When >>>>> nfsd_file_cache_shutdown() is then called it will clean up an rhltable >>>>> that has already been destroyed. We get exactly the reported symptom. >>>>> >>>>> I *think* nfsd_file_cache_init() can only fail with -ENOMEM and I would >>>>> expect to see a warning when that happened. In any case >>>>> nfsd_file_cache_init() uses pr_err() for any failure except >>>>> rhltable_init(), and that only fails if the params are inconsistent. >>>>> >>>>> So I think there are problems with NFSD_FILE_CACHE_UP settings and I >>>>> think they could trigger this bug if a kmalloc failed, but I don't think >>>>> that a kmalloc failed and I think there must be some other explanation >>>>> here. >>>> >>>> Also, the FILE_CACHE_UP logic has been around for several releases. >>>> Why is this UAF showing up only now? The "unable to register" >>>> messages suggest a possible reason. >>>> >>> >>> Good point. I didn't notice those. 111 is ECONNREFUSED, so it sounds >>> like rpcbind isn't up in this situation. Maybe that's a hint toward a >>> reproducer? >> >> I've enabled KASAN, shut down NFSD, and disabled rpcbind. >> Using the /proc/fs/nfsd/threads interface, I can reproduce >> the "unable to register" messages, but not the KASAN splat. >> >> I think Neil's analysis above is correct or very close. I >> don't have nfsdctl set up here, but my guess is that the >> syzbot is abusing the new netlink command API, causing >> nfsd_file_cache_init() to fail somehow and the error >> flow is leaving the kernel vulnerable to a UAF. > > > Based on the fact that it happened 8 times and no reproducer so far: > 1. Likely to be a true bug in nsfd > 2. LIkely to be a hard to trigger race condition > 3. The fact that alloc/free frequently don't match access tack > suggests that the access happens long after the free (pointer left in > some global structure) > > I also found one with matching stacks here: > https://syzkaller.appspot.com/text?tag=CrashLog&x=128bd39f980000 > > It looks like the object is freed during creation: > > [ 3239.085992][ T8199] __kmem_cache_create_args(nfsd_file) failed with error -22 > [ 3239.117916][ T8199] CPU: 1 UID: 0 PID: 8199 Comm: syz.1.6492 Not > tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 > [ 3239.129138][ T8199] Hardware name: Google Google Compute > Engine/Google Compute Engine, BIOS Google 09/13/2024 > [ 3239.139255][ T8199] Call Trace: > [ 3239.142756][ T8199] <TASK> > [ 3239.145753][ T8199] dump_stack_lvl+0x16c/0x1f0 > [ 3239.150510][ T8199] __kmem_cache_create_args+0x130/0x3c0 > [ 3239.156126][ T8199] nfsd_file_cache_init+0x126/0x4d0 > [ 3239.161408][ T8199] ? net_generic+0xf4/0x2a0 > [ 3239.165992][ T8199] nfsd_svc+0x5db/0x940 > [ 3239.170309][ T8199] nfsd_nl_threads_set_doit+0x535/0xbe0 > [ 3239.175933][ T8199] genl_family_rcv_msg_doit+0x202/0x2f0 > [ 3239.181560][ T8199] ? __pfx_genl_family_rcv_msg_doit+0x10/0x10 > [ 3239.187720][ T8199] ? bpf_lsm_capable+0x9/0x10 > [ 3239.192470][ T8199] ? security_capable+0x7e/0x260 > [ 3239.197482][ T8199] genl_rcv_msg+0x565/0x800 > [ 3239.202063][ T8199] ? __pfx_genl_rcv_msg+0x10/0x10 > [ 3239.207201][ T8199] ? __pfx_nfsd_nl_threads_set_doit+0x10/0x10 > [ 3239.213336][ T8199] netlink_rcv_skb+0x165/0x410 > [ 3239.218144][ T8199] ? __pfx_genl_rcv_msg+0x10/0x10 > [ 3239.223301][ T8199] ? __pfx_netlink_rcv_skb+0x10/0x10 > [ 3239.228636][ T8199] ? down_read+0xc9/0x330 > [ 3239.233012][ T8199] ? __pfx_down_read+0x10/0x10 > [ 3239.237833][ T8199] ? netlink_deliver_tap+0x1ae/0xcf0 > [ 3239.243429][ T8199] genl_rcv+0x28/0x40 > [ 3239.247447][ T8199] netlink_unicast+0x53c/0x7f0 > [ 3239.252257][ T8199] ? __pfx_netlink_unicast+0x10/0x10 > [ 3239.257579][ T8199] ? __phys_addr_symbol+0x30/0x80 > [ 3239.262641][ T8199] ? __check_object_size+0x488/0x710 > [ 3239.267972][ T8199] netlink_sendmsg+0x8b8/0xd70 > [ 3239.272776][ T8199] ? __pfx_netlink_sendmsg+0x10/0x10 > [ 3239.278115][ T8199] ____sys_sendmsg+0x9ae/0xb40 > [ 3239.282921][ T8199] ? copy_msghdr_from_user+0x10b/0x160 > [ 3239.288434][ T8199] ? __pfx_____sys_sendmsg+0x10/0x10 > [ 3239.293765][ T8199] ? netlink_recvmsg+0x81c/0xf30 > [ 3239.298736][ T8199] ? __pfx___lock_acquire+0x10/0x10 > [ 3239.303989][ T8199] ___sys_sendmsg+0x135/0x1e0 > [ 3239.308715][ T8199] ? __pfx____sys_sendmsg+0x10/0x10 > [ 3239.313976][ T8199] ? lock_acquire+0x2f/0xb0 > [ 3239.318521][ T8199] ? __fget_files+0x40/0x3f0 > [ 3239.323155][ T8199] ? fdget+0x176/0x210 > [ 3239.327348][ T8199] __sys_sendmsg+0x117/0x1f0 > [ 3239.331985][ T8199] ? __pfx___sys_sendmsg+0x10/0x10 > [ 3239.337153][ T8199] ? __x64_sys_futex+0x1e1/0x4c0 > [ 3239.342236][ T8199] do_syscall_64+0xcd/0x250 > [ 3239.346787][ T8199] entry_SYSCALL_64_after_hwframe+0x77/0x7f > [ 3239.352716][ T8199] RIP: 0033:0x7fd3c577dff9 > [ 3239.357157][ T8199] Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f > 1f 40 00 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 a8 ff ff ff f7 d8 > 64 89 01 48 > [ 3239.376798][ T8199] RSP: 002b:00007fd3c65a7038 EFLAGS: 00000246 > ORIG_RAX: 000000000000002e > [ 3239.385282][ T8199] RAX: ffffffffffffffda RBX: 00007fd3c5935f80 > RCX: 00007fd3c577dff9 > [ 3239.393282][ T8199] RDX: 0000000000008004 RSI: 0000000020000140 > RDI: 0000000000000006 > [ 3239.401287][ T8199] RBP: 00007fd3c57f0296 R08: 0000000000000000 > R09: 0000000000000000 > [ 3239.409291][ T8199] R10: 0000000000000000 R11: 0000000000000246 > R12: 0000000000000000 > [ 3239.417296][ T8199] R13: 0000000000000000 R14: 00007fd3c5935f80 > R15: 00007ffca7d46f08 > [ 3239.425314][ T8199] </TASK> > [ 3239.605040][ T8199] nfsd: unable to create nfsd_file_slab > [ 3242.331528][ T8252] netlink: zone id is out of range > [ 3242.353608][ T8252] netlink: zone id is out of range > [ 3242.375964][ T8252] netlink: zone id is out of range > [ 3242.381340][ T8252] netlink: zone id is out of range > [ 3242.432868][ T8252] netlink: zone id is out of range > [ 3242.506182][ T8252] netlink: zone id is out of range > [ 3242.529087][ T8252] netlink: zone id is out of range > [ 3242.574253][ T8252] netlink: zone id is out of range > [ 3245.016756][ T8292] sock: sock_set_timeout: `syz.3.6511' (pid 8292) > tries to set negative timeout > [ 3245.419913][ T8295] svc: failed to register nfsdv3 RPC service (errno 111). > [ 3245.467727][ T8295] svc: failed to register nfsaclv3 RPC service (errno 111). > [ 3245.693668][ T8295] > ================================================================== > [ 3245.701818][ T8295] BUG: KASAN: slab-use-after-free in > rhashtable_walk_enter+0x333/0x370 > [ 3245.710150][ T8295] Read of size 8 at addr ffff8880301ac010 by task > syz.1.6512/8295 > [ 3245.718011][ T8295] > [ 3245.720376][ T8295] CPU: 1 UID: 0 PID: 8295 Comm: syz.1.6512 Not > tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 > [ 3245.731118][ T8295] Hardware name: Google Google Compute > Engine/Google Compute Engine, BIOS Google 09/13/2024 > [ 3245.741404][ T8295] Call Trace: > [ 3245.744728][ T8295] <TASK> > [ 3245.747702][ T8295] dump_stack_lvl+0x116/0x1f0 > [ 3245.752629][ T8295] print_report+0xc3/0x620 > [ 3245.757152][ T8295] ? __virt_addr_valid+0x5e/0x590 > [ 3245.762261][ T8295] ? __phys_addr+0xc6/0x150 > [ 3245.766862][ T8295] kasan_report+0xd9/0x110 > [ 3245.771374][ T8295] ? rhashtable_walk_enter+0x333/0x370 > [ 3245.776919][ T8295] ? rhashtable_walk_enter+0x333/0x370 > [ 3245.782467][ T8295] rhashtable_walk_enter+0x333/0x370 > [ 3245.787843][ T8295] __nfsd_file_cache_purge+0xad/0x470 > [ 3245.793299][ T8295] ? __pfx___nfsd_file_cache_purge+0x10/0x10 > [ 3245.799445][ T8295] ? lockdep_hardirqs_on+0x7c/0x110 > [ 3245.804721][ T8295] ? enable_work+0x246/0x340 > [ 3245.809637][ T8295] ? __pfx_enable_work+0x10/0x10 > [ 3245.814651][ T8295] nfsd_file_cache_shutdown+0xcf/0x4e0 > [ 3245.820203][ T8295] nfsd_svc+0x6a9/0x940 > [ 3245.824435][ T8295] nfsd_nl_threads_set_doit+0x535/0xbe0 > [ 3245.830066][ T8295] genl_family_rcv_msg_doit+0x202/0x2f0 > [ 3245.835692][ T8295] ? __pfx_genl_family_rcv_msg_doit+0x10/0x10 > [ 3245.841845][ T8295] ? bpf_lsm_capable+0x9/0x10 > [ 3245.846733][ T8295] ? security_capable+0x7e/0x260 > [ 3245.851836][ T8295] genl_rcv_msg+0x565/0x800 > [ 3245.856427][ T8295] ? __pfx_genl_rcv_msg+0x10/0x10 > [ 3245.861530][ T8295] ? __pfx_nfsd_nl_threads_set_doit+0x10/0x10 > [ 3245.867684][ T8295] netlink_rcv_skb+0x165/0x410 > [ 3245.872559][ T8295] ? __pfx_genl_rcv_msg+0x10/0x10 > [ 3245.877679][ T8295] ? __pfx_netlink_rcv_skb+0x10/0x10 > [ 3245.883041][ T8295] ? down_read+0xc9/0x330 > [ 3245.887446][ T8295] ? __pfx_down_read+0x10/0x10 > [ 3245.892295][ T8295] ? netlink_deliver_tap+0x1ae/0xcf0 > [ 3245.897649][ T8295] genl_rcv+0x28/0x40 > [ 3245.901698][ T8295] netlink_unicast+0x53c/0x7f0 > [ 3245.906584][ T8295] ? __pfx_netlink_unicast+0x10/0x10 > [ 3245.912041][ T8295] ? __phys_addr_symbol+0x30/0x80 > [ 3245.917161][ T8295] ? __check_object_size+0x488/0x710 > [ 3245.922542][ T8295] netlink_sendmsg+0x8b8/0xd70 > [ 3245.927393][ T8295] ? __pfx_netlink_sendmsg+0x10/0x10 > [ 3245.932758][ T8295] ____sys_sendmsg+0x9ae/0xb40 > [ 3245.937616][ T8295] ? copy_msghdr_from_user+0x10b/0x160 > [ 3245.943164][ T8295] ? __pfx_____sys_sendmsg+0x10/0x10 > [ 3245.948531][ T8295] ? netlink_recvmsg+0x81c/0xf30 > [ 3245.953535][ T8295] ? __pfx___lock_acquire+0x10/0x10 > [ 3245.958906][ T8295] ___sys_sendmsg+0x135/0x1e0 > [ 3245.963667][ T8295] ? __pfx____sys_sendmsg+0x10/0x10 > [ 3245.968960][ T8295] ? lock_acquire+0x2f/0xb0 > [ 3245.973562][ T8295] ? __fget_files+0x40/0x3f0 > [ 3245.978240][ T8295] ? fdget+0x176/0x210 > [ 3245.982379][ T8295] __sys_sendmsg+0x117/0x1f0 > [ 3245.987050][ T8295] ? __pfx___sys_sendmsg+0x10/0x10 > [ 3245.992252][ T8295] ? __x64_sys_futex+0x1e1/0x4c0 > [ 3245.997285][ T8295] do_syscall_64+0xcd/0x250 > [ 3246.001884][ T8295] entry_SYSCALL_64_after_hwframe+0x77/0x7f > [ 3246.007856][ T8295] RIP: 0033:0x7fd3c577dff9 > [ 3246.012333][ T8295] Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f > 1f 40 00 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 a8 ff ff ff f7 d8 > 64 89 01 48 > [ 3246.032094][ T8295] RSP: 002b:00007fd3c65a7038 EFLAGS: 00000246 > ORIG_RAX: 000000000000002e > [ 3246.040597][ T8295] RAX: ffffffffffffffda RBX: 00007fd3c5935f80 > RCX: 00007fd3c577dff9 > [ 3246.048626][ T8295] RDX: 0000000000008004 RSI: 0000000020000140 > RDI: 0000000000000003 > [ 3246.056739][ T8295] RBP: 00007fd3c57f0296 R08: 0000000000000000 > R09: 0000000000000000 > [ 3246.064770][ T8295] R10: 0000000000000000 R11: 0000000000000246 > R12: 0000000000000000 > [ 3246.072801][ T8295] R13: 0000000000000000 R14: 00007fd3c5935f80 > R15: 00007ffca7d46f08 > [ 3246.080840][ T8295] </TASK> > [ 3246.083901][ T8295] > [ 3246.086354][ T8295] Allocated by task 8199: > [ 3246.090716][ T8295] kasan_save_stack+0x33/0x60 > [ 3246.095449][ T8295] kasan_save_track+0x14/0x30 > [ 3246.100192][ T8295] __kasan_kmalloc+0xaa/0xb0 > [ 3246.104861][ T8295] __kmalloc_node_noprof+0x211/0x440 > [ 3246.110263][ T8295] __kvmalloc_node_noprof+0xad/0x1a0 > [ 3246.115630][ T8295] bucket_table_alloc.isra.0+0x86/0x460 > [ 3246.121336][ T8295] rhashtable_init_noprof+0x43b/0x7d0 > [ 3246.126797][ T8295] rhltable_init_noprof+0x20/0x60 > [ 3246.131899][ T8295] nfsd_file_cache_init+0xd2/0x4d0 > [ 3246.137089][ T8295] nfsd_svc+0x5db/0x940 > [ 3246.141306][ T8295] nfsd_nl_threads_set_doit+0x535/0xbe0 > [ 3246.147008][ T8295] genl_family_rcv_msg_doit+0x202/0x2f0 > [ 3246.152628][ T8295] genl_rcv_msg+0x565/0x800 > [ 3246.157209][ T8295] netlink_rcv_skb+0x165/0x410 > [ 3246.162039][ T8295] genl_rcv+0x28/0x40 > [ 3246.166089][ T8295] netlink_unicast+0x53c/0x7f0 > [ 3246.170946][ T8295] netlink_sendmsg+0x8b8/0xd70 > [ 3246.175774][ T8295] ____sys_sendmsg+0x9ae/0xb40 > [ 3246.180605][ T8295] ___sys_sendmsg+0x135/0x1e0 > [ 3246.185447][ T8295] __sys_sendmsg+0x117/0x1f0 > [ 3246.190110][ T8295] do_syscall_64+0xcd/0x250 > [ 3246.194685][ T8295] entry_SYSCALL_64_after_hwframe+0x77/0x7f > [ 3246.200643][ T8295] > [ 3246.203001][ T8295] Freed by task 8199: > [ 3246.207011][ T8295] kasan_save_stack+0x33/0x60 > [ 3246.211840][ T8295] kasan_save_track+0x14/0x30 > [ 3246.216587][ T8295] kasan_save_free_info+0x3b/0x60 > [ 3246.221674][ T8295] __kasan_slab_free+0x51/0x70 > [ 3246.226594][ T8295] kfree+0x14f/0x4b0 > [ 3246.230547][ T8295] kvfree+0x47/0x50 > [ 3246.234426][ T8295] rhashtable_free_and_destroy+0x16c/0x990 > [ 3246.240316][ T8295] nfsd_file_cache_init+0x3e0/0x4d0 > [ 3246.245587][ T8295] nfsd_svc+0x5db/0x940 > [ 3246.249802][ T8295] nfsd_nl_threads_set_doit+0x535/0xbe0 > [ 3246.255425][ T8295] genl_family_rcv_msg_doit+0x202/0x2f0 > [ 3246.261048][ T8295] genl_rcv_msg+0x565/0x800 > [ 3246.265634][ T8295] netlink_rcv_skb+0x165/0x410 > [ 3246.270463][ T8295] genl_rcv+0x28/0x40 > [ 3246.274539][ T8295] netlink_unicast+0x53c/0x7f0 > [ 3246.279369][ T8295] netlink_sendmsg+0x8b8/0xd70 > [ 3246.284200][ T8295] ____sys_sendmsg+0x9ae/0xb40 > [ 3246.289023][ T8295] ___sys_sendmsg+0x135/0x1e0 > [ 3246.293760][ T8295] __sys_sendmsg+0x117/0x1f0 > [ 3246.298430][ T8295] do_syscall_64+0xcd/0x250 > [ 3246.303005][ T8295] entry_SYSCALL_64_after_hwframe+0x77/0x7f > [ 3246.308966][ T8295] > [ 3246.311330][ T8295] The buggy address belongs to the object at > ffff8880301ac000 > [ 3246.311330][ T8295] which belongs to the cache kmalloc-4k of size 4096 > [ 3246.325434][ T8295] The buggy address is located 16 bytes inside of > [ 3246.325434][ T8295] freed 4096-byte region [ffff8880301ac000, > ffff8880301ad000) > [ 3246.339289][ T8295] > [ 3246.341654][ T8295] The buggy address belongs to the physical page: > [ 3246.348116][ T8295] page: refcount:1 mapcount:0 > mapping:0000000000000000 index:0x0 pfn:0x301a8 > [ 3246.356987][ T8295] head: order:3 mapcount:0 entire_mapcount:0 > nr_pages_mapped:0 pincount:0 > [ 3246.365630][ T8295] flags: > 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) > [ 3246.373252][ T8295] page_type: f5(slab) > [ 3246.377291][ T8295] raw: 00fff00000000040 ffff88801ac42140 > ffffea0000db9800 dead000000000002 > [ 3246.385938][ T8295] raw: 0000000000000000 0000000000040004 > 00000001f5000000 0000000000000000 > [ 3246.394589][ T8295] head: 00fff00000000040 ffff88801ac42140 > ffffea0000db9800 dead000000000002 > [ 3246.403325][ T8295] head: 0000000000000000 0000000000040004 > 00000001f5000000 0000000000000000 > [ 3246.412047][ T8295] head: 00fff00000000003 ffffea0000c06a01 > ffffffffffffffff 0000000000000000 > [ 3246.420777][ T8295] head: 0000000000000008 0000000000000000 > 00000000ffffffff 0000000000000000 > [ 3246.429501][ T8295] page dumped because: kasan: bad access detected > [ 3246.435995][ T8295] page_owner tracks the page as allocated > [ 3246.441746][ T8295] page last allocated via order 3, migratetype > Unmovable, gfp_mask > 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), > pid 21493, tgid 21493 (syz.0.3187), ts 1292101106947, free_ts > 1292053895765 > [ 3246.462737][ T8295] post_alloc_hook+0x2d1/0x350 > [ 3246.467575][ T8295] get_page_from_freelist+0x101e/0x3070 > [ 3246.473199][ T8295] __alloc_pages_noprof+0x223/0x25c0 > [ 3246.478567][ T8295] alloc_pages_mpol_noprof+0x2c9/0x610 > [ 3246.484105][ T8295] new_slab+0x2ba/0x3f0 > [ 3246.488335][ T8295] ___slab_alloc+0xd1d/0x16f0 > [ 3246.493128][ T8295] __slab_alloc.constprop.0+0x56/0xb0 > [ 3246.498579][ T8295] __kmalloc_noprof+0x379/0x410 > [ 3246.503511][ T8295] tomoyo_realpath_from_path+0xbf/0x710 > [ 3246.509162][ T8295] tomoyo_check_open_permission+0x2a7/0x3b0 > [ 3246.515145][ T8295] tomoyo_file_open+0xcf/0x100 > [ 3246.519975][ T8295] security_file_open+0x64c/0x9d0 > [ 3246.525092][ T8295] do_dentry_open+0x57c/0x1530 > [ 3246.530014][ T8295] vfs_open+0x82/0x3f0 > [ 3246.534177][ T8295] path_openat+0x1e6a/0x2d60 > [ 3246.538831][ T8295] do_filp_open+0x1dc/0x430 > [ 3246.543412][ T8295] page last free pid 12198 tgid 12198 stack trace: > [ 3246.549952][ T8295] free_unref_page+0x5f4/0xdc0 > [ 3246.554884][ T8295] __put_partials+0x14c/0x170 > [ 3246.559637][ T8295] qlist_free_all+0x4e/0x120 > [ 3246.564302][ T8295] kasan_quarantine_reduce+0x192/0x1e0 > [ 3246.569924][ T8295] __kasan_slab_alloc+0x69/0x90 > [ 3246.574848][ T8295] kmem_cache_alloc_node_noprof+0x153/0x310 > [ 3246.580821][ T8295] __alloc_skb+0x2b3/0x380 > [ 3246.585351][ T8295] alloc_skb_with_frags+0xe4/0x850 > [ 3246.590526][ T8295] sock_alloc_send_pskb+0x7f1/0x980 > [ 3246.595806][ T8295] mld_newpack.isra.0+0x1d4/0x7e0 > [ 3246.600904][ T8295] add_grhead+0x299/0x340 > [ 3246.605299][ T8295] add_grec+0x111e/0x1670 > [ 3246.609696][ T8295] mld_ifc_work+0x41f/0xca0 > [ 3246.614273][ T8295] process_one_work+0x958/0x1b30 > [ 3246.619294][ T8295] worker_thread+0x6c8/0xf00 > [ 3246.623964][ T8295] kthread+0x2c1/0x3a0 > [ 3246.628104][ T8295] > [ 3246.630461][ T8295] Memory state around the buggy address: > [ 3246.636132][ T8295] ffff8880301abf00: fc fc fc fc fc fc fc fc fc > fc fc fc fc fc fc fc > [ 3246.644246][ T8295] ffff8880301abf80: fc fc fc fc fc fc fc fc fc > fc fc fc fc fc fc fc > [ 3246.652375][ T8295] >ffff8880301ac000: fa fb fb fb fb fb fb fb fb > fb fb fb fb fb fb fb > [ 3246.660488][ T8295] ^ > [ 3246.665151][ T8295] ffff8880301ac080: fb fb fb fb fb fb fb fb fb > fb fb fb fb fb fb fb > [ 3246.673265][ T8295] ffff8880301ac100: fb fb fb fb fb fb fb fb fb > fb fb fb fb fb fb fb > [ 3246.681390][ T8295] > ================================================================== This: https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?h=nfsd-fixes&id=dc0d0f885aa422f621bc1c2124133eff566b0bc8 is in the v6.12-rc pile. We think it addresses this crasher. -- Chuck Lever
