Re: net: sleeping function called from invalid context in net_enable_timestamp
From: Eric Dumazet <hidden>
Date: 2017-03-01 21:18:53
Also in:
lkml
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
On Wed, 2017-03-01 at 11:59 -0800, Eric Dumazet wrote:
On Wed, Mar 1, 2017 at 11:51 AM, Dmitry Vyukov [off-list ref] wrote:quoted
Hello, I've got the following report while running syzkaller fuzzer on e5d56efc97f8240d0b5d66c03949382b6d7e5570Right, a listener is playing fool games. We need to use a work queue for all net_enable_timestamp() invocations
Something like :
diff --git a/net/core/dev.c b/net/core/dev.c
index e63bf61b19be029e30ac40443c0e2edb24de4a73..10fac295f4d4dff983156e2cac22456db948b32b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -1702,15 +1702,27 @@ static void netstamp_clear(struct work_struct *work) { int deferred = atomic_xchg(&netstamp_needed_deferred, 0); - while (deferred--) + while (deferred < 0) { + deferred++; static_key_slow_dec(&netstamp_needed); + } + while (deferred > 0) { + deferred--; + static_key_slow_inc(&netstamp_needed); + } } static DECLARE_WORK(netstamp_work, netstamp_clear); #endif void net_enable_timestamp(void) { +#ifdef HAVE_JUMP_LABEL + /* net_enable_timestamp() can be called from non process context */ + atomic_inc(&netstamp_needed_deferred); + schedule_work(&netstamp_work); +#else static_key_slow_inc(&netstamp_needed); +#endif } EXPORT_SYMBOL(net_enable_timestamp);
@@ -1718,7 +1730,7 @@ void net_disable_timestamp(void) { #ifdef HAVE_JUMP_LABEL /* net_disable_timestamp() can be called from non process context */ - atomic_inc(&netstamp_needed_deferred); + atomic_dec(&netstamp_needed_deferred); schedule_work(&netstamp_work); #else static_key_slow_dec(&netstamp_needed);