On 1/23/22 8:29 AM, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
Hi,
FWIIW :
We picked up the suspect "Fixes" commit :
2020-10-01 | x86/kdump: Always reserve the low 1M when the crashkernel
option is specified
In an LTS update: 5.4.68, and I do not see the issue reported in the
summary : "DMA: preallocated 128 KiB GFP_KERNEL pool for atomic
allocations " , when a kdump is invoked. We test kdump quite regularly
on a variety of platforms.
Baoquan's series may not be needed in 5.4.LTS.
------------------ original commit in Linus's tree ------------------
From a674e48c5443d12a8a43c3ac42367aa39505d506 Mon Sep 17 00:00:00 2001
From: Baoquan He <bhe@xxxxxxxxxx>
Date: Fri, 14 Jan 2022 14:07:41 -0800
Subject: [PATCH] dma/pool: create dma atomic pool only if dma zone has managed
pages
Currently three dma atomic pools are initialized as long as the relevant
kernel codes are built in. While in kdump kernel of x86_64, this is not
right when trying to create atomic_pool_dma, because there's no managed
pages in DMA zone. In the case, DMA zone only has low 1M memory
presented and locked down by memblock allocator. So no pages are added
into buddy of DMA zone. Please check commit f1d4d47c5851 ("x86/setup:
Always reserve the first 1M of RAM").
Then in kdump kernel of x86_64, it always prints below failure message:
DMA: preallocated 128 KiB GFP_KERNEL pool for atomic allocations
swapper/0: page allocation failure: order:5, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.13.0-0.rc5.20210611git929d931f2b40.42.fc35.x86_64 #1
Hardware name: Dell Inc. PowerEdge R910/0P658H, BIOS 2.12.0 06/04/2018
Call Trace:
dump_stack+0x7f/0xa1
warn_alloc.cold+0x72/0xd6
__alloc_pages_slowpath.constprop.0+0xf29/0xf50
__alloc_pages+0x24d/0x2c0
alloc_page_interleave+0x13/0xb0
atomic_pool_expand+0x118/0x210
__dma_atomic_pool_init+0x45/0x93
dma_atomic_pool_init+0xdb/0x176
do_one_initcall+0x67/0x320
kernel_init_freeable+0x290/0x2dc
kernel_init+0xa/0x111
ret_from_fork+0x22/0x30
Mem-Info:
......
DMA: failed to allocate 128 KiB GFP_KERNEL|GFP_DMA pool for atomic allocation
DMA: preallocated 128 KiB GFP_KERNEL|GFP_DMA32 pool for atomic allocations
Here, let's check if DMA zone has managed pages, then create
atomic_pool_dma if yes. Otherwise just skip it.
Link: https://urldefense.com/v3/__https://lkml.kernel.org/r/20211223094435.248523-3-bhe@redhat.com__;!!ACWV5N9M2RV99hQ!b4MXpPOLvHa3lqMG3cEpMMlmORCR1Snd7RudCeFoVW_R6IVpPpsNKHKxn6dlZ2w60Ky7$
Fixes: 6f599d84231f ("x86/kdump: Always reserve the low 1M when the crashkernel option is specified")
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: John Donnelly <john.p.donnelly@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 5f84e6cdb78e..4d40dcce7604 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -203,7 +203,7 @@ static int __init dma_atomic_pool_init(void)
GFP_KERNEL);
if (!atomic_pool_kernel)
ret = -ENOMEM;
- if (IS_ENABLED(CONFIG_ZONE_DMA)) {
+ if (has_managed_dma()) {
atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
GFP_KERNEL | GFP_DMA);
if (!atomic_pool_dma)
@@ -226,7 +226,7 @@ static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp)
if (prev == NULL) {
if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
return atomic_pool_dma32;
- if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
+ if (atomic_pool_dma && (gfp & GFP_DMA))
return atomic_pool_dma;
return atomic_pool_kernel;
}
