* [alternative-merged] mm-utilc-make-kvfree-safe-for-calling-while-holding-spinlocks.patch removed from -mm tree
@ 2022-01-27 22:01 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2022-01-27 22:01 UTC (permalink / raw)
To: 1vier1, arnd, cgel.zte, chi.minghao, dbueso, manfred, mhocko,
mm-commits, rdunlap, shakeelb, stable, unixbhaskar, urezki, vvs,
zealci
The patch titled
Subject: mm/util.c: make kvfree() safe for calling while holding spinlocks
has been removed from the -mm tree. Its filename was
mm-utilc-make-kvfree-safe-for-calling-while-holding-spinlocks.patch
This patch was dropped because an alternative patch was merged
------------------------------------------------------
From: Manfred Spraul <manfred@colorfullife.com>
Subject: mm/util.c: make kvfree() safe for calling while holding spinlocks
One codepath in find_alloc_undo() calls kvfree() while holding a spinlock.
Since vfree() can sleep this is a bug.
Previously, the code path used kfree(), and kfree() is safe to be called
while holding a spinlock.
Minghao proposed to fix this by updating find_alloc_undo().
Alternate proposal to fix this: Instead of changing find_alloc_undo(),
change kvfree() so that the same rules as for kfree() apply: Having
different rules for kfree() and kvfree() just asks for bugs.
Disadvantage: Releasing vmalloc'ed memory will be delayed a bit.
Link: https://lkml.kernel.org/r/20211222194828.15320-1-manfred@colorfullife.com
Link: https://lore.kernel.org/all/20211222081026.484058-1-chi.minghao@zte.com.cn/
Fixes: fc37a3b8b438 ("[PATCH] ipc sem: use kvmalloc for sem_undo allocation")
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Reported-by: Zeal Robot <zealci@zte.com.cn>
Reported-by: Minghao Chi <chi.minghao@zte.com.cn>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: CGEL ZTE <cgel.zte@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <1vier1@web.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/util.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/util.c~mm-utilc-make-kvfree-safe-for-calling-while-holding-spinlocks
+++ a/mm/util.c
@@ -603,12 +603,12 @@ EXPORT_SYMBOL(kvmalloc_node);
* It is slightly more efficient to use kfree() or vfree() if you are certain
* that you know which one to use.
*
- * Context: Either preemptible task context or not-NMI interrupt.
+ * Context: Any context except NMI interrupt.
*/
void kvfree(const void *addr)
{
if (is_vmalloc_addr(addr))
- vfree(addr);
+ vfree_atomic(addr);
else
kfree(addr);
}
_
Patches currently in -mm which might be from manfred@colorfullife.com are
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2022-01-27 22:01 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-01-27 22:01 [alternative-merged] mm-utilc-make-kvfree-safe-for-calling-while-holding-spinlocks.patch removed from -mm tree akpm
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.