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Subject[PATCH 4.0 32/58] mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
Date
4.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Larry Finger <Larry.Finger@lwfinger.net>

commit 8a8c35fadfaf55629a37ef1a8ead1b8fb32581d2 upstream.

Beginning at commit d52d3997f843 ("ipv6: Create percpu rt6_info"), the
following INFO splat is logged:

===============================
[ INFO: suspicious RCU usage. ]
4.1.0-rc7-next-20150612 #1 Not tainted
-------------------------------
kernel/sched/core.c:7318 Illegal context switch in RCU-bh read-side critical section!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
3 locks held by systemd/1:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff815f0c8f>] rtnetlink_rcv+0x1f/0x40
#1: (rcu_read_lock_bh){......}, at: [<ffffffff816a34e2>] ipv6_add_addr+0x62/0x540
#2: (addrconf_hash_lock){+...+.}, at: [<ffffffff816a3604>] ipv6_add_addr+0x184/0x540
stack backtrace:
CPU: 0 PID: 1 Comm: systemd Not tainted 4.1.0-rc7-next-20150612 #1
Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20 04/17/2014
Call Trace:
dump_stack+0x4c/0x6e
lockdep_rcu_suspicious+0xe7/0x120
___might_sleep+0x1d5/0x1f0
__might_sleep+0x4d/0x90
kmem_cache_alloc+0x47/0x250
create_object+0x39/0x2e0
kmemleak_alloc_percpu+0x61/0xe0
pcpu_alloc+0x370/0x630

Additional backtrace lines are truncated. In addition, the above splat
is followed by several "BUG: sleeping function called from invalid
context at mm/slub.c:1268" outputs. As suggested by Martin KaFai Lau,
these are the clue to the fix. Routine kmemleak_alloc_percpu() always
uses GFP_KERNEL for its allocations, whereas it should follow the gfp
from its callers.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/kmemleak.h | 6 ++++--
mm/kmemleak.c | 9 +++++----
mm/percpu.c | 2 +-
3 files changed, 10 insertions(+), 7 deletions(-)

--- a/include/linux/kmemleak.h
+++ b/include/linux/kmemleak.h
@@ -28,7 +28,8 @@
extern void kmemleak_init(void) __ref;
extern void kmemleak_alloc(const void *ptr, size_t size, int min_count,
gfp_t gfp) __ref;
-extern void kmemleak_alloc_percpu(const void __percpu *ptr, size_t size) __ref;
+extern void kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
+ gfp_t gfp) __ref;
extern void kmemleak_free(const void *ptr) __ref;
extern void kmemleak_free_part(const void *ptr, size_t size) __ref;
extern void kmemleak_free_percpu(const void __percpu *ptr) __ref;
@@ -71,7 +72,8 @@ static inline void kmemleak_alloc_recurs
gfp_t gfp)
{
}
-static inline void kmemleak_alloc_percpu(const void __percpu *ptr, size_t size)
+static inline void kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
+ gfp_t gfp)
{
}
static inline void kmemleak_free(const void *ptr)
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -909,12 +909,13 @@ EXPORT_SYMBOL_GPL(kmemleak_alloc);
* kmemleak_alloc_percpu - register a newly allocated __percpu object
* @ptr: __percpu pointer to beginning of the object
* @size: size of the object
+ * @gfp: flags used for kmemleak internal memory allocations
*
* This function is called from the kernel percpu allocator when a new object
- * (memory block) is allocated (alloc_percpu). It assumes GFP_KERNEL
- * allocation.
+ * (memory block) is allocated (alloc_percpu).
*/
-void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size)
+void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
+ gfp_t gfp)
{
unsigned int cpu;

@@ -927,7 +928,7 @@ void __ref kmemleak_alloc_percpu(const v
if (kmemleak_enabled && ptr && !IS_ERR(ptr))
for_each_possible_cpu(cpu)
create_object((unsigned long)per_cpu_ptr(ptr, cpu),
- size, 0, GFP_KERNEL);
+ size, 0, gfp);
else if (kmemleak_early_log)
log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
}
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1030,7 +1030,7 @@ area_found:
memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);

ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
- kmemleak_alloc_percpu(ptr, size);
+ kmemleak_alloc_percpu(ptr, size, gfp);
return ptr;

fail_unlock:



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