> On Sep 18, 2024, at 2:55 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote: > > On Wed, Sep 18, 2024 at 09:26:27AM -0700, syzbot wrote: >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: 57719771a244 Merge tag 'sound-6.11' of git://git.kernel.or.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=122c17c7980000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=96be9a618e50f19f >> dashboard link: https://syzkaller.appspot.com/bug?extid=6926ab9f6f7d7b50002e >> 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=1559749f980000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1359749f980000 >> >> Downloadable assets: >> disk image: https://storage.googleapis.com/syzbot-assets/87498efcab61/disk-57719771.raw.xz >> vmlinux: https://storage.googleapis.com/syzbot-assets/5703d19e746c/vmlinux-57719771.xz >> kernel image: https://storage.googleapis.com/syzbot-assets/3744ba66862a/bzImage-57719771.xz >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+6926ab9f6f7d7b50002e@xxxxxxxxxxxxxxxxxxxxxxxxx >> >> svc: failed to register nfsdv3 RPC service (errno 512). >> svc: failed to register nfsaclv3 RPC service (errno 512). >> ================================================================== >> BUG: KASAN: slab-use-after-free in shrinker_free+0x3b7/0x430 mm/shrinker.c:775 >> Read of size 4 at addr ffff8880206cbb1c by task syz-executor313/5320 >> >> CPU: 0 UID: 0 PID: 5320 Comm: syz-executor313 Not tainted 6.11.0-rc7-syzkaller-00145-g57719771a244 #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 >> shrinker_free+0x3b7/0x430 mm/shrinker.c:775 >> nfsd_file_cache_shutdown+0xbc/0x480 fs/nfsd/filecache.c:891 >> 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 > > This looks like an issue with nfsd startup error handling (maybe > resulting in a double free?) and not a shrinker issue as such. > CC'ing the NFS people. This looks like a known problem that has presented with several different failure modes. One of the latest reports: https://lore.kernel.org/linux-nfs/adb93c51f6e34195716fd892049dc6e0f08b46aa.camel@xxxxxxxxxx/ I can't think of any risk for doing what Jeff suggested here, but I was hoping for some review by the author of 786615bc1ce8 ("SUNRPC: If the rpcbind channel is disconnected, fail the call to unregister"). >> 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+0x9b4/0xb50 net/socket.c:2597 >> ___sys_sendmsg+0x135/0x1e0 net/socket.c:2651 >> __sys_sendmsg+0x117/0x1f0 net/socket.c:2680 >> 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: 0033:0x7f51ae6e5ab9 >> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 1d 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 b0 ff ff ff f7 d8 64 89 01 48 >> RSP: 002b:00007f51ae634158 EFLAGS: 00000246 ORIG_RAX: 000000000000002e >> RAX: ffffffffffffffda RBX: 00007f51ae768438 RCX: 00007f51ae6e5ab9 >> RDX: 0000000000000004 RSI: 0000000020000280 RDI: 0000000000000003 >> RBP: 00007f51ae768430 R08: 0000000000000008 R09: 0000000000000000 >> R10: 0000000000000003 R11: 0000000000000246 R12: 00007f51ae76843c >> R13: 000000000000006e R14: 00007ffc1415e4a0 R15: 00007ffc1415e588 >> </TASK> >> >> Allocated by task 5309: >> 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 >> kmalloc_noprof include/linux/slab.h:681 [inline] >> kzalloc_noprof include/linux/slab.h:807 [inline] >> shrinker_alloc+0xf8/0xb00 mm/shrinker.c:683 >> nfsd_file_cache_init+0x152/0x450 fs/nfsd/filecache.c:743 >> nfsd_startup_generic fs/nfsd/nfssvc.c:307 [inline] >> nfsd_startup_net fs/nfsd/nfssvc.c:402 [inline] >> nfsd_svc+0x542/0x970 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+0x9b4/0xb50 net/socket.c:2597 >> ___sys_sendmsg+0x135/0x1e0 net/socket.c:2651 >> __sys_sendmsg+0x117/0x1f0 net/socket.c:2680 >> 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 >> >> Freed by task 0: >> 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:2256 [inline] >> slab_free mm/slub.c:4477 [inline] >> kfree+0x12a/0x3b0 mm/slub.c:4598 >> rcu_do_batch kernel/rcu/tree.c:2569 [inline] >> rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2843 >> handle_softirqs+0x216/0x8f0 kernel/softirq.c:554 >> __do_softirq kernel/softirq.c:588 [inline] >> invoke_softirq kernel/softirq.c:428 [inline] >> __irq_exit_rcu kernel/softirq.c:637 [inline] >> irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 >> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] >> sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 >> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 >> >> Last potentially related work creation: >> kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 >> __kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:541 >> __call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:3106 >> shrinker_free+0xfe/0x430 mm/shrinker.c:807 >> nfsd_file_cache_shutdown+0xbc/0x480 fs/nfsd/filecache.c:891 >> 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+0x9b4/0xb50 net/socket.c:2597 >> ___sys_sendmsg+0x135/0x1e0 net/socket.c:2651 >> __sys_sendmsg+0x117/0x1f0 net/socket.c:2680 >> 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 >> >> The buggy address belongs to the object at ffff8880206cbb00 >> which belongs to the cache kmalloc-192 of size 192 >> The buggy address is located 28 bytes inside of >> freed 192-byte region [ffff8880206cbb00, ffff8880206cbbc0) >> >> The buggy address belongs to the physical page: >> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x206cb >> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) >> page_type: 0xfdffffff(slab) >> raw: 00fff00000000000 ffff88801ac413c0 dead000000000100 dead000000000122 >> raw: 0000000000000000 0000000080100010 00000001fdffffff 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 4560085887, free_ts 0 >> 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:2325 >> allocate_slab mm/slub.c:2488 [inline] >> new_slab+0x84/0x260 mm/slub.c:2541 >> ___slab_alloc+0xdac/0x1870 mm/slub.c:3727 >> __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3817 >> __slab_alloc_node mm/slub.c:3870 [inline] >> slab_alloc_node mm/slub.c:4029 [inline] >> __kmalloc_cache_noprof+0x2c5/0x310 mm/slub.c:4188 >> kmalloc_noprof include/linux/slab.h:681 [inline] >> kzalloc_noprof include/linux/slab.h:807 [inline] >> call_usermodehelper_setup+0x9a/0x340 kernel/umh.c:363 >> kobject_uevent_env+0xde3/0x1670 lib/kobject_uevent.c:628 >> kset_register+0x1b6/0x2b0 lib/kobject.c:877 >> class_register+0x22e/0x340 drivers/base/class.c:203 >> typec_init+0x63/0x110 drivers/usb/typec/class.c:2518 >> do_one_initcall+0x128/0x630 init/main.c:1267 >> do_initcall_level init/main.c:1329 [inline] >> do_initcalls init/main.c:1345 [inline] >> do_basic_setup init/main.c:1364 [inline] >> kernel_init_freeable+0x660/0xc50 init/main.c:1578 >> kernel_init+0x1c/0x2b0 init/main.c:1467 >> page_owner free stack trace missing >> >> Memory state around the buggy address: >> ffff8880206cba00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >> ffff8880206cba80: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc >>> ffff8880206cbb00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ^ >> ffff8880206cbb80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >> ffff8880206cbc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >> ================================================================== >> >> >> --- >> 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 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 >> > > -- > Dave Chinner > david@xxxxxxxxxxxxx -- Chuck Lever
