Re: [PATCH v2 19/21] treewide: add checks for the return value of memblock_alloc*()

From: Christophe Leroy
Date: Thu Jan 31 2019 - 01:07:55 EST




Le 21/01/2019 Ã 09:04, Mike Rapoport a ÃcritÂ:
Add check for the return value of memblock_alloc*() functions and call
panic() in case of error.
The panic message repeats the one used by panicing memblock allocators with
adjustment of parameters to include only relevant ones.

The replacement was mostly automated with semantic patches like the one
below with manual massaging of format strings.

@@
expression ptr, size, align;
@@
ptr = memblock_alloc(size, align);
+ if (!ptr)
+ panic("%s: Failed to allocate %lu bytes align=0x%lx\n", __func__,
size, align);

Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Reviewed-by: Guo Ren <ren_guo@xxxxxxxxx> # c-sky
Acked-by: Paul Burton <paul.burton@xxxxxxxx> # MIPS
Acked-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> # s390
Reviewed-by: Juergen Gross <jgross@xxxxxxxx> # Xen
---

[...]

diff --git a/mm/sparse.c b/mm/sparse.c
index 7ea5dc6..ad94242 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c

[...]

@@ -425,6 +436,10 @@ static void __init sparse_buffer_init(unsigned long size, int nid)
memblock_alloc_try_nid_raw(size, PAGE_SIZE,
__pa(MAX_DMA_ADDRESS),
MEMBLOCK_ALLOC_ACCESSIBLE, nid);
+ if (!sparsemap_buf)
+ panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%lx\n",
+ __func__, size, PAGE_SIZE, nid, __pa(MAX_DMA_ADDRESS));
+

memblock_alloc_try_nid_raw() does not panic (help explicitly says: Does not zero allocated memory, does not panic if request cannot be satisfied.).

Stephen Rothwell reports a boot failure due to this change.

Christophe

sparsemap_buf_end = sparsemap_buf + size;
}