diff options
author | Davide Caratti <dcaratti@redhat.com> | 2019-10-19 18:34:35 +0300 |
---|---|---|
committer | Simon Horman <horms@verge.net.au> | 2019-10-24 12:53:19 +0300 |
commit | 62931f59ce9cbabb934a431f48f2f1f441c605ac (patch) | |
tree | d7a95131984d9cfcab34ba6856eabc51d284a230 | |
parent | 085461c8976e6cb4d5b608a7b7062f394c51a253 (diff) | |
download | linux-62931f59ce9cbabb934a431f48f2f1f441c605ac.tar.xz |
ipvs: don't ignore errors in case refcounting ip_vs module fails
if the IPVS module is removed while the sync daemon is starting, there is
a small gap where try_module_get() might fail getting the refcount inside
ip_vs_use_count_inc(). Then, the refcounts of IPVS module are unbalanced,
and the subsequent call to stop_sync_thread() causes the following splat:
WARNING: CPU: 0 PID: 4013 at kernel/module.c:1146 module_put.part.44+0x15b/0x290
Modules linked in: ip_vs(-) nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 veth ip6table_filter ip6_tables iptable_filter binfmt_misc intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul ext4 mbcache jbd2 ghash_clmulni_intel snd_hda_codec_generic ledtrig_audio snd_hda_intel snd_intel_nhlt snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd cryptd glue_helper joydev pcspkr snd_timer virtio_balloon snd soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c ata_generic pata_acpi virtio_net net_failover virtio_blk failover virtio_console qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ata_piix ttm crc32c_intel serio_raw drm virtio_pci libata virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod [last unloaded: nf_defrag_ipv6]
CPU: 0 PID: 4013 Comm: modprobe Tainted: G W 5.4.0-rc1.upstream+ #741
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:module_put.part.44+0x15b/0x290
Code: 04 25 28 00 00 00 0f 85 18 01 00 00 48 83 c4 68 5b 5d 41 5c 41 5d 41 5e 41 5f c3 89 44 24 28 83 e8 01 89 c5 0f 89 57 ff ff ff <0f> 0b e9 78 ff ff ff 65 8b 1d 67 83 26 4a 89 db be 08 00 00 00 48
RSP: 0018:ffff888050607c78 EFLAGS: 00010297
RAX: 0000000000000003 RBX: ffffffffc1420590 RCX: ffffffffb5db0ef9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffffc1420590
RBP: 00000000ffffffff R08: fffffbfff82840b3 R09: fffffbfff82840b3
R10: 0000000000000001 R11: fffffbfff82840b2 R12: 1ffff1100a0c0f90
R13: ffffffffc1420200 R14: ffff88804f533300 R15: ffff88804f533ca0
FS: 00007f8ea9720740(0000) GS:ffff888053800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3245abe000 CR3: 000000004c28a006 CR4: 00000000001606f0
Call Trace:
stop_sync_thread+0x3a3/0x7c0 [ip_vs]
ip_vs_sync_net_cleanup+0x13/0x50 [ip_vs]
ops_exit_list.isra.5+0x94/0x140
unregister_pernet_operations+0x29d/0x460
unregister_pernet_device+0x26/0x60
ip_vs_cleanup+0x11/0x38 [ip_vs]
__x64_sys_delete_module+0x2d5/0x400
do_syscall_64+0xa5/0x4e0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f8ea8bf0db7
Code: 73 01 c3 48 8b 0d b9 80 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 89 80 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffcd38d2fe8 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
RAX: ffffffffffffffda RBX: 0000000002436240 RCX: 00007f8ea8bf0db7
RDX: 0000000000000000 RSI: 0000000000000800 RDI: 00000000024362a8
RBP: 0000000000000000 R08: 00007f8ea8eba060 R09: 00007f8ea8c658a0
R10: 00007ffcd38d2a60 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000001 R14: 00000000024362a8 R15: 0000000000000000
irq event stamp: 4538
hardirqs last enabled at (4537): [<ffffffffb6193dde>] quarantine_put+0x9e/0x170
hardirqs last disabled at (4538): [<ffffffffb5a0556a>] trace_hardirqs_off_thunk+0x1a/0x20
softirqs last enabled at (4522): [<ffffffffb6f8ebe9>] sk_common_release+0x169/0x2d0
softirqs last disabled at (4520): [<ffffffffb6f8eb3e>] sk_common_release+0xbe/0x2d0
Check the return value of ip_vs_use_count_inc() and let its caller return
proper error. Inside do_ip_vs_set_ctl() the module is already refcounted,
we don't need refcount/derefcount there. Finally, in register_ip_vs_app()
and start_sync_thread(), take the module refcount earlier and ensure it's
released in the error path.
Change since v1:
- better return values in case of failure of ip_vs_use_count_inc(),
thanks to Julian Anastasov
- no need to increase/decrease the module refcount in ip_vs_set_ctl(),
thanks to Julian Anastasov
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
-rw-r--r-- | net/netfilter/ipvs/ip_vs_app.c | 12 | ||||
-rw-r--r-- | net/netfilter/ipvs/ip_vs_ctl.c | 14 | ||||
-rw-r--r-- | net/netfilter/ipvs/ip_vs_pe.c | 3 | ||||
-rw-r--r-- | net/netfilter/ipvs/ip_vs_sched.c | 3 | ||||
-rw-r--r-- | net/netfilter/ipvs/ip_vs_sync.c | 13 |
5 files changed, 28 insertions, 17 deletions
diff --git a/net/netfilter/ipvs/ip_vs_app.c b/net/netfilter/ipvs/ip_vs_app.c index 4515056ef1c2..f9b16f2b2219 100644 --- a/net/netfilter/ipvs/ip_vs_app.c +++ b/net/netfilter/ipvs/ip_vs_app.c @@ -193,21 +193,29 @@ struct ip_vs_app *register_ip_vs_app(struct netns_ipvs *ipvs, struct ip_vs_app * mutex_lock(&__ip_vs_app_mutex); + /* increase the module use count */ + if (!ip_vs_use_count_inc()) { + err = -ENOENT; + goto out_unlock; + } + list_for_each_entry(a, &ipvs->app_list, a_list) { if (!strcmp(app->name, a->name)) { err = -EEXIST; + /* decrease the module use count */ + ip_vs_use_count_dec(); goto out_unlock; } } a = kmemdup(app, sizeof(*app), GFP_KERNEL); if (!a) { err = -ENOMEM; + /* decrease the module use count */ + ip_vs_use_count_dec(); goto out_unlock; } INIT_LIST_HEAD(&a->incs_list); list_add(&a->a_list, &ipvs->app_list); - /* increase the module use count */ - ip_vs_use_count_inc(); out_unlock: mutex_unlock(&__ip_vs_app_mutex); diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index 8b48e7ce1c2c..c8f81dd15c83 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -1275,7 +1275,8 @@ ip_vs_add_service(struct netns_ipvs *ipvs, struct ip_vs_service_user_kern *u, struct ip_vs_service *svc = NULL; /* increase the module use count */ - ip_vs_use_count_inc(); + if (!ip_vs_use_count_inc()) + return -ENOPROTOOPT; /* Lookup the scheduler by 'u->sched_name' */ if (strcmp(u->sched_name, "none")) { @@ -2435,9 +2436,6 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) if (copy_from_user(arg, user, len) != 0) return -EFAULT; - /* increase the module use count */ - ip_vs_use_count_inc(); - /* Handle daemons since they have another lock */ if (cmd == IP_VS_SO_SET_STARTDAEMON || cmd == IP_VS_SO_SET_STOPDAEMON) { @@ -2450,13 +2448,13 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) ret = -EINVAL; if (strscpy(cfg.mcast_ifn, dm->mcast_ifn, sizeof(cfg.mcast_ifn)) <= 0) - goto out_dec; + return ret; cfg.syncid = dm->syncid; ret = start_sync_thread(ipvs, &cfg, dm->state); } else { ret = stop_sync_thread(ipvs, dm->state); } - goto out_dec; + return ret; } mutex_lock(&__ip_vs_mutex); @@ -2551,10 +2549,6 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) out_unlock: mutex_unlock(&__ip_vs_mutex); - out_dec: - /* decrease the module use count */ - ip_vs_use_count_dec(); - return ret; } diff --git a/net/netfilter/ipvs/ip_vs_pe.c b/net/netfilter/ipvs/ip_vs_pe.c index 8e104dff7abc..166c669f0763 100644 --- a/net/netfilter/ipvs/ip_vs_pe.c +++ b/net/netfilter/ipvs/ip_vs_pe.c @@ -68,7 +68,8 @@ int register_ip_vs_pe(struct ip_vs_pe *pe) struct ip_vs_pe *tmp; /* increase the module use count */ - ip_vs_use_count_inc(); + if (!ip_vs_use_count_inc()) + return -ENOENT; mutex_lock(&ip_vs_pe_mutex); /* Make sure that the pe with this name doesn't exist diff --git a/net/netfilter/ipvs/ip_vs_sched.c b/net/netfilter/ipvs/ip_vs_sched.c index 2f9d5cd5daee..d4903723be7e 100644 --- a/net/netfilter/ipvs/ip_vs_sched.c +++ b/net/netfilter/ipvs/ip_vs_sched.c @@ -179,7 +179,8 @@ int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) } /* increase the module use count */ - ip_vs_use_count_inc(); + if (!ip_vs_use_count_inc()) + return -ENOENT; mutex_lock(&ip_vs_sched_mutex); diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c index a4a78c4b06de..8dc892a9dc91 100644 --- a/net/netfilter/ipvs/ip_vs_sync.c +++ b/net/netfilter/ipvs/ip_vs_sync.c @@ -1762,6 +1762,10 @@ int start_sync_thread(struct netns_ipvs *ipvs, struct ipvs_sync_daemon_cfg *c, IP_VS_DBG(7, "Each ip_vs_sync_conn entry needs %zd bytes\n", sizeof(struct ip_vs_sync_conn_v0)); + /* increase the module use count */ + if (!ip_vs_use_count_inc()) + return -ENOPROTOOPT; + /* Do not hold one mutex and then to block on another */ for (;;) { rtnl_lock(); @@ -1892,9 +1896,6 @@ int start_sync_thread(struct netns_ipvs *ipvs, struct ipvs_sync_daemon_cfg *c, mutex_unlock(&ipvs->sync_mutex); rtnl_unlock(); - /* increase the module use count */ - ip_vs_use_count_inc(); - return 0; out: @@ -1924,11 +1925,17 @@ out: } kfree(ti); } + + /* decrease the module use count */ + ip_vs_use_count_dec(); return result; out_early: mutex_unlock(&ipvs->sync_mutex); rtnl_unlock(); + + /* decrease the module use count */ + ip_vs_use_count_dec(); return result; } |