From 2c8468dcf8303c68712f11c782d7d8724de07a73 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 5 Sep 2017 08:31:23 -0700 Subject: [PATCH] net: sched: don't use GFP_KERNEL under spin lock The new TC IDR code uses GFP_KERNEL under spin lock. Which leads to: [ 582.621091] BUG: sleeping function called from invalid context at ../mm/slab.h:416 [ 582.629721] in_atomic(): 1, irqs_disabled(): 0, pid: 3379, name: tc [ 582.636939] 2 locks held by tc/3379: [ 582.641049] #0: (rtnl_mutex){+.+.+.}, at: [] rtnetlink_rcv_msg+0x92e/0x1400 [ 582.650958] #1: (&(&tn->idrinfo->lock)->rlock){+.-.+.}, at: [] tcf_idr_create+0x2f0/0x8e0 [ 582.662217] Preemption disabled at: [ 582.662222] [] tcf_idr_create+0x2f0/0x8e0 [ 582.672592] CPU: 9 PID: 3379 Comm: tc Tainted: G W 4.13.0-rc7-debug-00648-g43503a79b9f0 #287 [ 582.683432] Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.3.4 11/08/2016 [ 582.691937] Call Trace: ... [ 582.742460] kmem_cache_alloc+0x286/0x540 [ 582.747055] radix_tree_node_alloc.constprop.6+0x4a/0x450 [ 582.753209] idr_get_free_cmn+0x627/0xf80 ... [ 582.815525] idr_alloc_cmn+0x1a8/0x270 ... [ 582.833804] tcf_idr_create+0x31b/0x8e0 ... Try to preallocate the memory with idr_prealloc(GFP_KERNEL) (as suggested by Eric Dumazet), and change the allocation flags under spin lock. Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR") Signed-off-by: Jakub Kicinski Reviewed-by: Simon Horman Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/act_api.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 0eb545bcb247..a306974e2fb4 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -296,10 +296,12 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est, spin_lock_init(&p->tcfa_lock); /* user doesn't specify an index */ if (!index) { + idr_preload(GFP_KERNEL); spin_lock_bh(&idrinfo->lock); err = idr_alloc_ext(idr, NULL, &idr_index, 1, 0, - GFP_KERNEL); + GFP_ATOMIC); spin_unlock_bh(&idrinfo->lock); + idr_preload_end(); if (err) { err3: free_percpu(p->cpu_qstats); @@ -307,10 +309,12 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est, } p->tcfa_index = idr_index; } else { + idr_preload(GFP_KERNEL); spin_lock_bh(&idrinfo->lock); err = idr_alloc_ext(idr, NULL, NULL, index, index + 1, - GFP_KERNEL); + GFP_ATOMIC); spin_unlock_bh(&idrinfo->lock); + idr_preload_end(); if (err) goto err3; p->tcfa_index = index;