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From: rppt@linux.ibm.com (Mike Rapoport)
To: linux-snps-arc@lists.infradead.org
Subject: [PATCH v2 19/21] treewide: add checks for the return value of memblock_alloc*()
Date: Thu, 31 Jan 2019 09:14:59 +0200	[thread overview]
Message-ID: <20190131071459.GC28876@rapoport-lnx> (raw)
In-Reply-To: <d5e4ff5b-d33a-e641-8159-d4f83bc28d0b@c-s.fr>

On Thu, Jan 31, 2019@08:07:29AM +0100, Christophe Leroy wrote:
> 
> 
> Le 31/01/2019 ? 07:44, Christophe Leroy a ?crit?:
> >
> >
> >Le 31/01/2019 ? 07:41, Mike Rapoport a ?crit?:
> >>On Thu, Jan 31, 2019@07:07:46AM +0100, Christophe Leroy wrote:
> >>>
> >>>
> >>>Le 21/01/2019 ? 09:04, Mike Rapoport a ?crit?:
> >>>>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 at linux.ibm.com>
> >>>>Reviewed-by: Guo Ren <ren_guo at c-sky.com>???????????? # c-sky
> >>>>Acked-by: Paul Burton <paul.burton at mips.com>???????? # MIPS
> >>>>Acked-by: Heiko Carstens <heiko.carstens at de.ibm.com> # s390
> >>>>Reviewed-by: Juergen Gross <jgross at suse.com>???????? # 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.).
> >>
> >>"Does not panic" does not mean it always succeeds.
> >
> >I agree, but at least here you are changing the behaviour by making it
> >panic explicitly. Are we sure there are not cases where the system could
> >just continue functionning ? Maybe a WARN_ON() would be enough there ?
> 
> Looking more in details, it looks like everything is done to live with
> sparsemap_buf NULL, all functions using it check it so having it NULL
> shouldn't imply a panic I believe, see code below.

You are right, I'm preparing the fix right now.
 
> static void *sparsemap_buf __meminitdata;
> static void *sparsemap_buf_end __meminitdata;
> 
> static void __init sparse_buffer_init(unsigned long size, int nid)
> {
> 	WARN_ON(sparsemap_buf);	/* forgot to call sparse_buffer_fini()? */
> 	sparsemap_buf =
> 		memblock_alloc_try_nid_raw(size, PAGE_SIZE,
> 						__pa(MAX_DMA_ADDRESS),
> 						MEMBLOCK_ALLOC_ACCESSIBLE, nid);
> 	sparsemap_buf_end = sparsemap_buf + size;
> }
> 
> static void __init sparse_buffer_fini(void)
> {
> 	unsigned long size = sparsemap_buf_end - sparsemap_buf;
> 
> 	if (sparsemap_buf && size > 0)
> 		memblock_free_early(__pa(sparsemap_buf), size);
> 	sparsemap_buf = NULL;
> }
> 
> void * __meminit sparse_buffer_alloc(unsigned long size)
> {
> 	void *ptr = NULL;
> 
> 	if (sparsemap_buf) {
> 		ptr = PTR_ALIGN(sparsemap_buf, size);
> 		if (ptr + size > sparsemap_buf_end)
> 			ptr = NULL;
> 		else
> 			sparsemap_buf = ptr + size;
> 	}
> 	return ptr;
> }
> 
> 
> Christophe
> 

-- 
Sincerely yours,
Mike.

  reply	other threads:[~2019-01-31  7:14 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-21  8:03 [PATCH v2 00/21] Refine memblock API Mike Rapoport
2019-01-21  8:03 ` [PATCH v2 01/21] openrisc: prefer memblock APIs returning virtual address Mike Rapoport
2019-01-27  3:07   ` Stafford Horne
2019-01-21  8:03 ` [PATCH v2 02/21] powerpc: use memblock functions " Mike Rapoport
2019-01-29  9:52   ` Michael Ellerman
2019-01-21  8:03 ` [PATCH v2 03/21] memblock: replace memblock_alloc_base(ANYWHERE) with memblock_phys_alloc Mike Rapoport
2019-01-21  8:03 ` [PATCH v2 04/21] memblock: drop memblock_alloc_base_nid() Mike Rapoport
2019-01-21  8:03 ` [PATCH v2 05/21] memblock: emphasize that memblock_alloc_range() returns a physical address Mike Rapoport
2019-01-21  8:03 ` [PATCH v2 06/21] memblock: memblock_phys_alloc_try_nid(): don't panic Mike Rapoport
2019-01-25 17:45   ` Catalin Marinas
2019-01-25 19:32     ` Mike Rapoport
2019-01-29  9:56   ` Michael Ellerman
2019-01-29  9:58     ` Michael Ellerman
2019-01-21  8:03 ` [PATCH v2 07/21] memblock: memblock_phys_alloc(): " Mike Rapoport
2019-01-21  8:03 ` [PATCH v2 08/21] memblock: drop __memblock_alloc_base() Mike Rapoport
2019-01-21  8:03 ` [PATCH v2 09/21] memblock: drop memblock_alloc_base() Mike Rapoport
2019-01-29 10:29   ` Michael Ellerman
2019-01-21  8:03 ` [PATCH v2 10/21] memblock: refactor internal allocation functions Mike Rapoport
2019-02-03  9:39   ` Michael Ellerman
2019-02-03 10:04     ` Mike Rapoport
2019-01-21  8:03 ` [PATCH v2 11/21] memblock: make memblock_find_in_range_node() and choose_memblock_flags() static Mike Rapoport
2019-01-21  8:03 ` [PATCH v2 12/21] arch: use memblock_alloc() instead of memblock_alloc_from(size, align, 0) Mike Rapoport
2019-01-21  8:04 ` [PATCH v2 13/21] arch: don't memset(0) memory returned by memblock_alloc() Mike Rapoport
2019-01-21  8:04 ` [PATCH v2 14/21] ia64: add checks for the return value of memblock_alloc*() Mike Rapoport
2019-01-21  8:04 ` [PATCH v2 15/21] sparc: " Mike Rapoport
2019-01-21  8:04 ` [PATCH v2 16/21] mm/percpu: " Mike Rapoport
2019-01-21  8:04 ` [PATCH v2 17/21] init/main: " Mike Rapoport
2019-01-21  8:04 ` [PATCH v2 18/21] swiotlb: " Mike Rapoport
2019-01-21  8:04 ` [PATCH v2 19/21] treewide: " Mike Rapoport
2019-01-21  8:39   ` Geert Uytterhoeven
2019-01-21 17:18   ` Rob Herring
2019-01-31  6:07   ` Christophe Leroy
2019-01-31  6:41     ` Mike Rapoport
2019-01-31  6:44       ` Christophe Leroy
2019-01-31  7:07         ` Christophe Leroy
2019-01-31  7:14           ` Mike Rapoport [this message]
2019-01-31 15:23   ` Max Filippov
2019-01-21  8:04 ` [PATCH v2 20/21] memblock: memblock_alloc_try_nid: don't panic Mike Rapoport
2019-01-21  8:04 ` [PATCH v2 21/21] memblock: drop memblock_alloc_*_nopanic() variants Mike Rapoport
2019-01-30 13:38   ` Petr Mladek
2019-09-24 17:52 ` [PATCH v2 00/21] Refine memblock API Adam Ford
2019-09-25 12:12   ` Fabio Estevam
2019-09-25 12:17     ` Adam Ford
2019-09-25 15:17       ` Fabio Estevam
2019-09-26 13:09         ` Adam Ford
2019-09-26 16:04           ` Mike Rapoport
2019-09-26 19:35             ` Adam Ford
2019-09-28  7:33               ` Mike Rapoport
2019-09-29 13:33                 ` Adam Ford
2019-10-02  0:14                   ` Adam Ford
2019-10-02  7:36                     ` Mike Rapoport
2019-10-02 11:14                       ` Adam Ford

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