From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@kernel.org>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
linux-mm@kvack.org, Andrii Nakryiko <andrii@kernel.org>
Subject: [PATCH sl-b 3/6] rcu: Make call_rcu() print allocation address of double-freed callback
Date: Fri, 4 Dec 2020 16:40:54 -0800 [thread overview]
Message-ID: <20201205004057.32199-3-paulmck@kernel.org> (raw)
In-Reply-To: <20201205004022.GA31166@paulmck-ThinkPad-P72>
From: "Paul E. McKenney" <paulmck@kernel.org>
The debug-object double-free checks in __call_rcu() print out the
RCU callback function, which is usually sufficient to track down the
double free. However, all uses of things like queue_rcu_work() will
have the same RCU callback function (rcu_work_rcufn() in this case),
so a diagnostic message for a double queue_rcu_work() needs more than
just the callback function.
This commit therefore prints the last allocation address of the
double-freed callback when the callback is slab-allocated and sufficient
debugging is enabled. It uses the shiny new kmem_last_alloc() and
kmem_last_alloc_errstring() functions for this purpose.
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b6c9c49..788a072 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2957,6 +2957,8 @@ static void check_cb_ovld(struct rcu_data *rdp)
static void
__call_rcu(struct rcu_head *head, rcu_callback_t func)
{
+ void *allocaddr;
+ const char *allocerr;
unsigned long flags;
struct rcu_data *rdp;
bool was_alldone;
@@ -2970,8 +2972,14 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func)
* Use rcu:rcu_callback trace event to find the previous
* time callback was passed to __call_rcu().
*/
- WARN_ONCE(1, "__call_rcu(): Double-freed CB %p->%pS()!!!\n",
- head, head->func);
+ allocaddr = kmem_last_alloc(head);
+ allocerr = kmem_last_alloc_errstring(allocaddr);
+ if (allocerr)
+ WARN_ONCE(1, "__call_rcu(): Double-freed CB %p->%pS()!!! (%s)\n",
+ head, head->func, allocerr);
+ else
+ WARN_ONCE(1, "__call_rcu(): Double-freed CB %p->%pS()!!! (Allocated at %pS)\n",
+ head, head->func, allocaddr);
WRITE_ONCE(head->func, rcu_leak_callback);
return;
}
--
2.9.5
next prev parent reply other threads:[~2020-12-05 0:42 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-05 0:40 [PATCH RFC sl-b] Export return addresses for better diagnostics Paul E. McKenney
2020-12-05 0:40 ` [PATCH sl-b 1/6] mm: Add kmem_last_alloc() to return last allocation for memory block paulmck
2020-12-07 9:02 ` Joonsoo Kim
2020-12-07 17:25 ` Paul E. McKenney
2020-12-08 8:57 ` Joonsoo Kim
2020-12-08 15:17 ` Paul E. McKenney
2020-12-05 0:40 ` [PATCH sl-b 2/6] mm: Add kmem_last_alloc_errstring() to provide more kmem_last_alloc() info paulmck
2020-12-05 0:40 ` paulmck [this message]
2020-12-05 0:40 ` [PATCH sl-b 4/6] mm: Create kmem_last_alloc_stack() to provide stack trace in slub paulmck
2020-12-05 0:40 ` [PATCH sl-b 5/6] percpu_ref: Print allocator upon reference-count underflow paulmck
2020-12-05 0:40 ` [PATCH sl-b 6/6] percpu_ref: Print stack trace " paulmck
2020-12-09 1:11 ` [PATCH RFC v2 sl-b] Export return addresses etc. for better diagnostics Paul E. McKenney
2020-12-09 1:12 ` [PATCH v2 sl-b 1/5] mm: Add mem_dump_obj() to print source of memory block paulmck
2020-12-09 8:17 ` Christoph Hellwig
2020-12-09 14:57 ` Paul E. McKenney
2020-12-09 17:53 ` Christoph Hellwig
2020-12-09 17:59 ` Paul E. McKenney
2020-12-09 17:28 ` Vlastimil Babka
2020-12-09 23:04 ` Paul E. McKenney
2020-12-10 10:48 ` Vlastimil Babka
2020-12-10 19:56 ` Paul E. McKenney
2020-12-10 12:04 ` Joonsoo Kim
2020-12-10 23:41 ` Paul E. McKenney
2020-12-09 1:13 ` [PATCH v2 sl-b 2/5] mm: Make mem_dump_obj() handle NULL and zero-sized pointers paulmck
2020-12-09 17:48 ` Vlastimil Babka
2020-12-10 3:25 ` Paul E. McKenney
2020-12-09 1:13 ` [PATCH v2 sl-b 3/5] mm: Make mem_dump_obj() handle vmalloc() memory paulmck
2020-12-09 17:51 ` Vlastimil Babka
2020-12-09 19:39 ` Uladzislau Rezki
2020-12-09 23:23 ` Paul E. McKenney
2020-12-10 10:49 ` Vlastimil Babka
2020-12-09 19:36 ` Uladzislau Rezki
2020-12-09 19:42 ` Paul E. McKenney
2020-12-09 20:04 ` Uladzislau Rezki
2020-12-09 1:13 ` [PATCH v2 sl-b 4/5] rcu: Make call_rcu() print mem_dump_obj() info for double-freed callback paulmck
2020-12-09 1:13 ` [PATCH v2 sl-b 5/5] percpu_ref: Dump mem_dump_obj() info upon reference-count underflow paulmck
2020-12-11 1:19 ` [PATCH RFC v2 sl-b] Export return addresses etc. for better diagnostics Paul E. McKenney
2020-12-11 1:19 ` [PATCH v3 sl-b 1/6] mm: Add mem_dump_obj() to print source of memory block paulmck
2020-12-11 2:22 ` Joonsoo Kim
2020-12-11 3:33 ` Paul E. McKenney
2020-12-11 3:42 ` Paul E. McKenney
2020-12-11 6:58 ` Joonsoo Kim
2020-12-11 16:59 ` Paul E. McKenney
2020-12-11 6:54 ` Joonsoo Kim
2020-12-11 1:19 ` [PATCH v3 sl-b 2/6] mm: Make mem_dump_obj() handle NULL and zero-sized pointers paulmck
2020-12-11 1:20 ` [PATCH v3 sl-b 3/6] mm: Make mem_dump_obj() handle vmalloc() memory paulmck
2020-12-11 1:20 ` [PATCH v3 sl-b 4/6] mm: Make mem_obj_dump() vmalloc() dumps include start and length paulmck
2020-12-11 1:20 ` [PATCH v3 sl-b 5/6] rcu: Make call_rcu() print mem_dump_obj() info for double-freed callback paulmck
2020-12-11 1:20 ` [PATCH v3 sl-b 6/6] percpu_ref: Dump mem_dump_obj() info upon reference-count underflow paulmck
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