This is a note to let you know that I've just added the patch titled
Revert "mm: kfence: apply kmemleak_ignore_phys on early allocated pool"
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-mm-kfence-apply-kmemleak_ignore_phys-on-early-allocated-pool.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From elver@xxxxxxxxxx Wed Aug 17 19:23:19 2022
From: Marco Elver <elver@xxxxxxxxxx>
Date: Tue, 16 Aug 2022 18:36:41 +0200
Subject: Revert "mm: kfence: apply kmemleak_ignore_phys on early allocated pool"
To: elver@xxxxxxxxxx, stable@xxxxxxxxxxxxxxx, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>, Dmitry Vyukov <dvyukov@xxxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, kasan-dev@xxxxxxxxxxxxxxxx, linux-mm@xxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, Will Deacon <will@xxxxxxxxxx>, Catalin Marinas <catalin.marinas@xxxxxxx>, Yee Lee <yee.lee@xxxxxxxxxxxx>, Max Schulze <max.schulze@xxxxxxxxx>
Message-ID: <20220816163641.2359996-1-elver@xxxxxxxxxx>
From: Marco Elver <elver@xxxxxxxxxx>
This reverts commit 07313a2b29ed1079eaa7722624544b97b3ead84b.
Commit 0c24e061196c21d5 ("mm: kmemleak: add rbtree and store physical
address for objects allocated with PA") is not yet in 5.19 (but appears
in 6.0). Without 0c24e061196c21d5, kmemleak still stores phys objects
and non-phys objects in the same tree, and ignoring (instead of freeing)
will cause insertions into the kmemleak object tree by the slab
post-alloc hook to conflict with the pool object (see comment).
Reports such as the following would appear on boot, and effectively
disable kmemleak:
| kmemleak: Cannot insert 0xffffff806e24f000 into the object search tree (overlaps existing)
| CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-v8-0815+ #5
| Hardware name: Raspberry Pi Compute Module 4 Rev 1.0 (DT)
| Call trace:
| dump_backtrace.part.0+0x1dc/0x1ec
| show_stack+0x24/0x80
| dump_stack_lvl+0x8c/0xb8
| dump_stack+0x1c/0x38
| create_object.isra.0+0x490/0x4b0
| kmemleak_alloc+0x3c/0x50
| kmem_cache_alloc+0x2f8/0x450
| __proc_create+0x18c/0x400
| proc_create_reg+0x54/0xd0
| proc_create_seq_private+0x94/0x120
| init_mm_internals+0x1d8/0x248
| kernel_init_freeable+0x188/0x388
| kernel_init+0x30/0x150
| ret_from_fork+0x10/0x20
| kmemleak: Kernel memory leak detector disabled
| kmemleak: Object 0xffffff806e24d000 (size 2097152):
| kmemleak: comm "swapper", pid 0, jiffies 4294892296
| kmemleak: min_count = -1
| kmemleak: count = 0
| kmemleak: flags = 0x5
| kmemleak: checksum = 0
| kmemleak: backtrace:
| kmemleak_alloc_phys+0x94/0xb0
| memblock_alloc_range_nid+0x1c0/0x20c
| memblock_alloc_internal+0x88/0x100
| memblock_alloc_try_nid+0x148/0x1ac
| kfence_alloc_pool+0x44/0x6c
| mm_init+0x28/0x98
| start_kernel+0x178/0x3e8
| __primary_switched+0xc4/0xcc
Reported-by: Max Schulze <max.schulze@xxxxxxxxx>
Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Link: https://lore.kernel.org/all/b33b33bc-2d06-1bcd-2df7-43678962b728@xxxxxxxxx/
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/kfence/core.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -603,6 +603,14 @@ static unsigned long kfence_init_pool(vo
addr += 2 * PAGE_SIZE;
}
+ /*
+ * The pool is live and will never be deallocated from this point on.
+ * Remove the pool object from the kmemleak object tree, as it would
+ * otherwise overlap with allocations returned by kfence_alloc(), which
+ * are registered with kmemleak through the slab post-alloc hook.
+ */
+ kmemleak_free(__kfence_pool);
+
return 0;
}
@@ -615,16 +623,8 @@ static bool __init kfence_init_pool_earl
addr = kfence_init_pool();
- if (!addr) {
- /*
- * The pool is live and will never be deallocated from this point on.
- * Ignore the pool object from the kmemleak phys object tree, as it would
- * otherwise overlap with allocations returned by kfence_alloc(), which
- * are registered with kmemleak through the slab post-alloc hook.
- */
- kmemleak_ignore_phys(__pa(__kfence_pool));
+ if (!addr)
return true;
- }
/*
* Only release unprotected pages, and do not try to go back and change
Patches currently in stable-queue which might be from elver@xxxxxxxxxx are
queue-5.19/revert-mm-kfence-apply-kmemleak_ignore_phys-on-early-allocated-pool.patch
