4.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Lebrun dlebrun@google.com
[ Upstream commit 191f86ca8ef27f7a492fd1c03620498c6e94f0ac ]
The seg6_build_state() function is called with RCU read lock held, so we cannot use GFP_KERNEL. This patch uses GFP_ATOMIC instead.
[ 92.770271] ============================= [ 92.770628] WARNING: suspicious RCU usage [ 92.770921] 4.16.0-rc4+ #12 Not tainted [ 92.771277] ----------------------------- [ 92.771585] ./include/linux/rcupdate.h:302 Illegal context switch in RCU read-side critical section! [ 92.772279] [ 92.772279] other info that might help us debug this: [ 92.772279] [ 92.773067] [ 92.773067] rcu_scheduler_active = 2, debug_locks = 1 [ 92.773514] 2 locks held by ip/2413: [ 92.773765] #0: (rtnl_mutex){+.+.}, at: [<00000000e5461720>] rtnetlink_rcv_msg+0x441/0x4d0 [ 92.774377] #1: (rcu_read_lock){....}, at: [<00000000df4f161e>] lwtunnel_build_state+0x59/0x210 [ 92.775065] [ 92.775065] stack backtrace: [ 92.775371] CPU: 0 PID: 2413 Comm: ip Not tainted 4.16.0-rc4+ #12 [ 92.775791] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc27 04/01/2014 [ 92.776608] Call Trace: [ 92.776852] dump_stack+0x7d/0xbc [ 92.777130] __schedule+0x133/0xf00 [ 92.777393] ? unwind_get_return_address_ptr+0x50/0x50 [ 92.777783] ? __sched_text_start+0x8/0x8 [ 92.778073] ? rcu_is_watching+0x19/0x30 [ 92.778383] ? kernel_text_address+0x49/0x60 [ 92.778800] ? __kernel_text_address+0x9/0x30 [ 92.779241] ? unwind_get_return_address+0x29/0x40 [ 92.779727] ? pcpu_alloc+0x102/0x8f0 [ 92.780101] _cond_resched+0x23/0x50 [ 92.780459] __mutex_lock+0xbd/0xad0 [ 92.780818] ? pcpu_alloc+0x102/0x8f0 [ 92.781194] ? seg6_build_state+0x11d/0x240 [ 92.781611] ? save_stack+0x9b/0xb0 [ 92.781965] ? __ww_mutex_wakeup_for_backoff+0xf0/0xf0 [ 92.782480] ? seg6_build_state+0x11d/0x240 [ 92.782925] ? lwtunnel_build_state+0x1bd/0x210 [ 92.783393] ? ip6_route_info_create+0x687/0x1640 [ 92.783846] ? ip6_route_add+0x74/0x110 [ 92.784236] ? inet6_rtm_newroute+0x8a/0xd0
Fixes: 6c8702c60b886 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels") Signed-off-by: David Lebrun dlebrun@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/seg6_iptunnel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -419,7 +419,7 @@ static int seg6_build_state(struct nlatt
slwt = seg6_lwt_lwtunnel(newts);
- err = dst_cache_init(&slwt->cache, GFP_KERNEL); + err = dst_cache_init(&slwt->cache, GFP_ATOMIC); if (err) { kfree(newts); return err;