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From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Julien Grall <julien@xen.org>, Wei Liu <wl@xen.org>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <ian.jackson@citrix.com>
Subject: [PATCH 1/2] lockprof: don't leave locks uninitialized upon allocation failure
Date: Thu, 23 Jul 2020 12:51:53 +0200	[thread overview]
Message-ID: <7c4f50ce-6212-2f16-c9c5-c9af450b10ba@suse.com> (raw)
In-Reply-To: <47f5478d-2f46-656c-0882-121aebc77f39@suse.com>

Even if a specific struct lock_profile instance can't be allocated, the
lock itself should still be functional. As this isn't a production use
feature, also log a message in the event that the profiling struct can't
be allocated.

Fixes: d98feda5c756 ("Make lock profiling usable again")
Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -103,10 +103,16 @@ struct lock_profile_qhead {
     do {                                                                      \
         struct lock_profile *prof;                                            \
         prof = xzalloc(struct lock_profile);                                  \
-        if (!prof) break;                                                     \
+        (s)->l = (spinlock_t)_SPIN_LOCK_UNLOCKED(prof);                       \
+        if ( !prof )                                                          \
+        {                                                                     \
+            printk(XENLOG_WARNING                                             \
+                   "lock profiling unavailable for %p(%d)'s " #l "\n",        \
+                   s, (s)->profile_head.idx);                                 \
+            break;                                                            \
+        }                                                                     \
         prof->name = #l;                                                      \
         prof->lock = &(s)->l;                                                 \
-        (s)->l = (spinlock_t)_SPIN_LOCK_UNLOCKED(prof);                       \
         prof->next = (s)->profile_head.elem_q;                                \
         (s)->profile_head.elem_q = prof;                                      \
     } while(0)



  reply	other threads:[~2020-07-23 10:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-23 10:50 [PATCH 0/2] lockprof: eliminate a minor bug and a quirk Jan Beulich
2020-07-23 10:51 ` Jan Beulich [this message]
2020-07-23 11:23   ` [PATCH 1/2] lockprof: don't leave locks uninitialized upon allocation failure Andrew Cooper
2020-07-23 11:26     ` Jan Beulich
2020-07-23 10:52 ` [PATCH 2/2] lockprof: don't pass name into registration function Jan Beulich
2020-07-23 11:27   ` Andrew Cooper

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