From 37f1c63e3e29181ad412485eec2200cffc1dc70f Mon Sep 17 00:00:00 2001 From: Roman Mashak Date: Fri, 24 Feb 2017 17:36:58 -0500 Subject: [PATCH] net sched actions: do not overwrite status of action creation. nla_memdup_cookie was overwriting err value, declared at function scope and earlier initialized with result of ->init(). At success nla_memdup_cookie() returns 0, and thus module refcnt decremented, although the action was installed. $ sudo tc actions add action pass index 1 cookie 1234 $ sudo tc actions ls action gact action order 0: gact action pass random type none pass val 0 index 1 ref 1 bind 0 $ $ lsmod Module Size Used by act_gact 16384 0 ... $ $ sudo rmmod act_gact [ 52.310283] ------------[ cut here ]------------ [ 52.312551] WARNING: CPU: 1 PID: 455 at kernel/module.c:1113 module_put+0x99/0xa0 [ 52.316278] Modules linked in: act_gact(-) crct10dif_pclmul crc32_pclmul ghash_clmulni_intel psmouse pcbc evbug aesni_intel aes_x86_64 crypto_simd serio_raw glue_helper pcspkr cryptd [ 52.322285] CPU: 1 PID: 455 Comm: rmmod Not tainted 4.10.0+ #11 [ 52.324261] Call Trace: [ 52.325132] dump_stack+0x63/0x87 [ 52.326236] __warn+0xd1/0xf0 [ 52.326260] warn_slowpath_null+0x1d/0x20 [ 52.326260] module_put+0x99/0xa0 [ 52.326260] tcf_hashinfo_destroy+0x7f/0x90 [ 52.326260] gact_exit_net+0x27/0x40 [act_gact] [ 52.326260] ops_exit_list.isra.6+0x38/0x60 [ 52.326260] unregister_pernet_operations+0x90/0xe0 [ 52.326260] unregister_pernet_subsys+0x21/0x30 [ 52.326260] tcf_unregister_action+0x68/0xa0 [ 52.326260] gact_cleanup_module+0x17/0xa0f [act_gact] [ 52.326260] SyS_delete_module+0x1ba/0x220 [ 52.326260] entry_SYSCALL_64_fastpath+0x1e/0xad [ 52.326260] RIP: 0033:0x7f527ffae367 [ 52.326260] RSP: 002b:00007ffeb402a598 EFLAGS: 00000202 ORIG_RAX: 00000000000000b0 [ 52.326260] RAX: ffffffffffffffda RBX: 0000559b069912a0 RCX: 00007f527ffae367 [ 52.326260] RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559b06991308 [ 52.326260] RBP: 0000000000000003 R08: 00007f5280264420 R09: 00007ffeb4029511 [ 52.326260] R10: 000000000000087b R11: 0000000000000202 R12: 00007ffeb4029580 [ 52.326260] R13: 0000000000000000 R14: 0000000000000000 R15: 0000559b069912a0 [ 52.354856] ---[ end trace 90d89401542b0db6 ]--- $ With the fix: $ sudo modprobe act_gact $ lsmod Module Size Used by act_gact 16384 0 ... $ sudo tc actions add action pass index 1 cookie 1234 $ sudo tc actions ls action gact action order 0: gact action pass random type none pass val 0 index 1 ref 1 bind 0 $ $ lsmod Module Size Used by act_gact 16384 1 ... $ sudo rmmod act_gact rmmod: ERROR: Module act_gact is in use $ $ sudo /home/mrv/bin/tc actions del action gact index 1 $ sudo rmmod act_gact $ lsmod Module Size Used by $ Fixes: 1045ba77a ("net sched actions: Add support for user cookies") Signed-off-by: Roman Mashak Signed-off-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- net/sched/act_api.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sched/act_api.c b/net/sched/act_api.c index dfe64f81cb16..b70aa57319ea 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -613,8 +613,8 @@ struct tc_action *tcf_action_init_1(struct net *net, struct nlattr *nla, goto err_mod; } - err = nla_memdup_cookie(a, tb); - if (err < 0) { + if (nla_memdup_cookie(a, tb) < 0) { + err = -ENOMEM; tcf_hash_release(a, bind); goto err_mod; } -- 2.20.1