From: cbouatmailru@gmail•com (Anton Vorontsov)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH RFC 0/4] ARM/KGDB: Some fixes for SMP machines
Date: Wed, 7 Jul 2010 21:54:06 +0400 [thread overview]
Message-ID: <20100707175406.GA28424@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <20100707171222.GA16448@oksana.dev.rtsoft.ru>
On Wed, Jul 07, 2010 at 09:12:22PM +0400, Anton Vorontsov wrote:
[...]
> 2. The patches are against a heavily patched kernel, and so far
> I didn't rebase them onto the 'debug core' rework as found
> in the very latest mainline kernels. I'll rebase the patches
> soon, so for now this is just an RFC.
BTW, I'm testing with another small fixup applied, I didn't send
it as a patch because this deadlock was already fixed in the
debug_core implementation (which KGDB is using nowadays). But
for the completeness, here it is:
(Don't deadlock if there's a wannabe-master CPUs, which entered
KGDB via exception, not NMI/IPI).
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index e7a2274..65bf75d 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -1522,7 +1522,9 @@ return_normal:
* from the debugger.
*/
for_each_online_cpu(i) {
- while (atomic_read(&cpu_in_kgdb[i]))
+ while (atomic_read(&cpu_in_kgdb[i]) &&
+ !(kgdb_info[i].exception_state &
+ DCPU_WANT_MASTER))
cpu_relax();
}
}
next prev parent reply other threads:[~2010-07-07 17:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-07 17:12 [PATCH RFC 0/4] ARM/KGDB: Some fixes for SMP machines Anton Vorontsov
2010-07-07 17:13 ` [PATCH RFC 1/4] ARM: kgdb: Must poll for IPIs during busy-waiting Anton Vorontsov
2010-07-07 17:13 ` [PATCH RFC 2/4] ARM: kgdb: Disable preemption before re-enabling interrupts Anton Vorontsov
2010-07-07 17:13 ` [PATCH RFC 3/4] net: Implement napi_try_disable() Anton Vorontsov
2010-07-07 17:13 ` [PATCH RFC 4/4] kgdb: Quiesce IO back-end before rounding up secondary CPUs Anton Vorontsov
2010-07-07 17:54 ` Anton Vorontsov [this message]
2010-07-08 8:48 ` [PATCH RFC 0/4] ARM/KGDB: Some fixes for SMP machines Will Deacon
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