syzbot has found a reproducer for the following issue on: HEAD commit: 252c765bd764 riscv, bpf: Add BPF exception tables git tree: bpf-next console output: https://syzkaller.appspot.com/x/log.txt?x=165fc0f4b00000 kernel config: https://syzkaller.appspot.com/x/.config?x=f60548b4c38ae4a8 dashboard link: https://syzkaller.appspot.com/bug?extid=67f89551088ea1a6850e compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1797fcf2b00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e71f9f300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+67f89551088ea1a6850e@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in __ptr_ring_peek include/linux/ptr_ring.h:172 [inline] BUG: KASAN: use-after-free in __ptr_ring_consume include/linux/ptr_ring.h:299 [inline] BUG: KASAN: use-after-free in veth_xdp_rcv+0x70b/0x810 drivers/net/veth.c:856 Read of size 8 at addr ffff88807af6e008 by task ksoftirqd/0/13 CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.15.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:256 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 __ptr_ring_peek include/linux/ptr_ring.h:172 [inline] __ptr_ring_consume include/linux/ptr_ring.h:299 [inline] veth_xdp_rcv+0x70b/0x810 drivers/net/veth.c:856 veth_poll+0x134/0x850 drivers/net/veth.c:913 __napi_poll+0xaf/0x440 net/core/dev.c:6993 napi_poll net/core/dev.c:7060 [inline] net_rx_action+0x801/0xb40 net/core/dev.c:7147 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 run_ksoftirqd kernel/softirq.c:920 [inline] run_ksoftirqd+0x2d/0x60 kernel/softirq.c:912 smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 7543: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] ____kasan_kmalloc mm/kasan/common.c:472 [inline] __kasan_kmalloc+0xa4/0xd0 mm/kasan/common.c:522 kmalloc_node include/linux/slab.h:614 [inline] kvmalloc_node+0x61/0x120 mm/util.c:587 kvmalloc include/linux/mm.h:805 [inline] kvmalloc_array include/linux/mm.h:823 [inline] __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:471 [inline] ptr_ring_init include/linux/ptr_ring.h:489 [inline] __veth_napi_enable_range+0xa2/0x780 drivers/net/veth.c:941 __veth_napi_enable drivers/net/veth.c:964 [inline] veth_enable_xdp+0x30f/0x620 drivers/net/veth.c:1068 veth_xdp_set drivers/net/veth.c:1483 [inline] veth_xdp+0x4d4/0x780 drivers/net/veth.c:1523 dev_xdp_install+0xd5/0x270 net/core/dev.c:9365 dev_xdp_attach+0x83d/0x1010 net/core/dev.c:9513 dev_xdp_attach_link net/core/dev.c:9532 [inline] bpf_xdp_link_attach+0x262/0x410 net/core/dev.c:9695 link_create kernel/bpf/syscall.c:4268 [inline] __sys_bpf+0x549c/0x5df0 kernel/bpf/syscall.c:4667 __do_sys_bpf kernel/bpf/syscall.c:4701 [inline] __se_sys_bpf kernel/bpf/syscall.c:4699 [inline] __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4699 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 7542: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1700 [inline] slab_free_freelist_hook+0x81/0x190 mm/slub.c:1725 slab_free mm/slub.c:3483 [inline] kfree+0xe4/0x530 mm/slub.c:4543 kvfree+0x42/0x50 mm/util.c:620 ptr_ring_cleanup include/linux/ptr_ring.h:671 [inline] veth_napi_del_range+0x3aa/0x560 drivers/net/veth.c:985 veth_napi_del drivers/net/veth.c:991 [inline] veth_disable_xdp+0x2b3/0x430 drivers/net/veth.c:1101 veth_xdp_set drivers/net/veth.c:1499 [inline] veth_xdp+0x698/0x780 drivers/net/veth.c:1523 dev_xdp_install+0x1ed/0x270 net/core/dev.c:9365 dev_xdp_detach_link net/core/dev.c:9549 [inline] bpf_xdp_link_release+0x242/0x4e0 net/core/dev.c:9564 bpf_link_free+0xe6/0x1b0 kernel/bpf/syscall.c:2427 bpf_link_put+0x161/0x1b0 kernel/bpf/syscall.c:2453 bpf_link_release+0x33/0x40 kernel/bpf/syscall.c:2461 __fput+0x288/0x9f0 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline] exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff88807af6e000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 8 bytes inside of 2048-byte region [ffff88807af6e000, ffff88807af6e800) The buggy address belongs to the page: page:ffffea0001ebda00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7af68 head:ffffea0001ebda00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888010c42000 raw: 0000000000000000 0000000000080008 00000001ffffffff 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 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 7536, ts 1019839663090, free_ts 1019749588025 prep_new_page mm/page_alloc.c:2424 [inline] get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4153 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5375 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2197 alloc_slab_page mm/slub.c:1763 [inline] allocate_slab mm/slub.c:1900 [inline] new_slab+0x319/0x490 mm/slub.c:1963 ___slab_alloc+0x921/0xfe0 mm/slub.c:2994 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3081 slab_alloc_node mm/slub.c:3172 [inline] __kmalloc_node_track_caller+0x2d2/0x340 mm/slub.c:4936 kmalloc_reserve net/core/skbuff.c:352 [inline] pskb_expand_head+0x15e/0x1060 net/core/skbuff.c:1699 netlink_trim+0x1ea/0x240 net/netlink/af_netlink.c:1296 netlink_broadcast+0x5b/0xd50 net/netlink/af_netlink.c:1492 nlmsg_multicast include/net/netlink.h:1033 [inline] nlmsg_notify+0x8f/0x280 net/netlink/af_netlink.c:2528 rtnl_notify net/core/rtnetlink.c:730 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:3833 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:3848 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:3836 [inline] rtnetlink_event+0x193/0x1d0 net/core/rtnetlink.c:5623 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1996 call_netdevice_notifiers_extack net/core/dev.c:2008 [inline] call_netdevice_notifiers net/core/dev.c:2022 [inline] netdev_features_change net/core/dev.c:1368 [inline] netdev_update_features net/core/dev.c:10035 [inline] netdev_update_features+0xc4/0xd0 net/core/dev.c:10032 veth_xdp_set drivers/net/veth.c:1510 [inline] veth_xdp+0x448/0x780 drivers/net/veth.c:1523 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1338 [inline] free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1389 free_unref_page_prepare mm/page_alloc.c:3315 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3394 __unfreeze_partials+0x340/0x360 mm/slub.c:2495 qlink_free mm/kasan/quarantine.c:146 [inline] qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272 __kasan_slab_alloc+0x95/0xb0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3206 [inline] slab_alloc mm/slub.c:3214 [inline] kmem_cache_alloc+0x209/0x390 mm/slub.c:3219 vm_area_dup+0x88/0x2b0 kernel/fork.c:357 __split_vma+0xa5/0x550 mm/mmap.c:2714 split_vma+0x95/0xd0 mm/mmap.c:2772 mprotect_fixup+0x678/0x940 mm/mprotect.c:477 do_mprotect_pkey+0x558/0x9a0 mm/mprotect.c:636 __do_sys_mprotect mm/mprotect.c:662 [inline] __se_sys_mprotect mm/mprotect.c:659 [inline] __x64_sys_mprotect+0x74/0xb0 mm/mprotect.c:659 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff88807af6df00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807af6df80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807af6e000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807af6e080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807af6e100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================
