* [PATCH v2 0/3] a few cleanup and bugfixes about shmem @ 2022-06-05 3:55 Chen Wandun 2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun ` (2 more replies) 0 siblings, 3 replies; 8+ messages in thread From: Chen Wandun @ 2022-06-05 3:55 UTC (permalink / raw) To: hughd, akpm, linux-mm, linux-kernel, willy, david, wangkefeng.wang v1 ==> v2: combine patch2 and patch3 into a single patch. Chen Wandun (3): mm/shmem: check return value of shmem_init_inodecache mm/shmem: return error code directly for invalid addr mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area mm/shmem.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) -- 2.25.1 ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache 2022-06-05 3:55 [PATCH v2 0/3] a few cleanup and bugfixes about shmem Chen Wandun @ 2022-06-05 3:55 ` Chen Wandun 2022-06-05 11:49 ` Matthew Wilcox 2022-06-05 3:55 ` [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr Chen Wandun 2022-06-05 3:55 ` [PATCH v2 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area Chen Wandun 2 siblings, 1 reply; 8+ messages in thread From: Chen Wandun @ 2022-06-05 3:55 UTC (permalink / raw) To: hughd, akpm, linux-mm, linux-kernel, willy, david, wangkefeng.wang It will result in null pointer access if shmem_init_inodecache fail, so check return value of shmem_init_inodecache Signed-off-by: Chen Wandun <chenwandun@huawei.com> --- mm/shmem.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 12d45a03f7fc..17f8297ece29 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -3775,11 +3775,13 @@ static void shmem_init_inode(void *foo) inode_init_once(&info->vfs_inode); } -static void shmem_init_inodecache(void) +static struct kmem_cache *shmem_init_inodecache(void) { shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", sizeof(struct shmem_inode_info), 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); + + return shmem_inode_cachep; } static void shmem_destroy_inodecache(void) @@ -3923,7 +3925,10 @@ void __init shmem_init(void) { int error; - shmem_init_inodecache(); + if (!shmem_init_inodecache()) { + error = -ENOMEM; + goto out2; + } error = register_filesystem(&shmem_fs_type); if (error) { -- 2.25.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache 2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun @ 2022-06-05 11:49 ` Matthew Wilcox 2022-06-06 1:34 ` Chen Wandun 0 siblings, 1 reply; 8+ messages in thread From: Matthew Wilcox @ 2022-06-05 11:49 UTC (permalink / raw) To: Chen Wandun; +Cc: hughd, akpm, linux-mm, linux-kernel, david, wangkefeng.wang On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote: > It will result in null pointer access if shmem_init_inodecache fail, > so check return value of shmem_init_inodecache You ignored my suggestion from v1. Here, let me write it out for you. +static int shmem_init_inodecache(void) { shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", sizeof(struct shmem_inode_info), 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); + if (!shmem_inode_cachep) + return -ENOMEM; + return 0; } ... + error = shmem_init_inodecache(); + if (error) + goto out2; ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache 2022-06-05 11:49 ` Matthew Wilcox @ 2022-06-06 1:34 ` Chen Wandun 2022-06-06 2:08 ` Matthew Wilcox 0 siblings, 1 reply; 8+ messages in thread From: Chen Wandun @ 2022-06-06 1:34 UTC (permalink / raw) To: Matthew Wilcox Cc: hughd, akpm, linux-mm, linux-kernel, david, wangkefeng.wang On 2022/6/5 19:49, Matthew Wilcox wrote: > On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote: >> It will result in null pointer access if shmem_init_inodecache fail, >> so check return value of shmem_init_inodecache > You ignored my suggestion from v1. Here, let me write it out for you. Hi Matthew, I didn't ignore your suggestion, some explanation is needed, sorry for that. In V1, Kefeng point: "kmem_cache_create return a pointer to the cache on success, NULL on failure, so error = -ENOMEM; is right :)" so, I look some similar code such as init_inodecache in kinds of file system, they all return -ENOMEM on failure, so is it OK to return -ENOMEM on failure :) Besides, kmem_cache_create return NULL on failure, maybe returning error code on failure is more proper, but it is another job. > > +static int shmem_init_inodecache(void) > { > shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", > sizeof(struct shmem_inode_info), > 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); > + if (!shmem_inode_cachep) > + return -ENOMEM; > + return 0; > } > > ... > > + error = shmem_init_inodecache(); > + if (error) > + goto out2; > > > . ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache 2022-06-06 1:34 ` Chen Wandun @ 2022-06-06 2:08 ` Matthew Wilcox 2022-06-06 2:58 ` Chen Wandun 0 siblings, 1 reply; 8+ messages in thread From: Matthew Wilcox @ 2022-06-06 2:08 UTC (permalink / raw) To: Chen Wandun; +Cc: hughd, akpm, linux-mm, linux-kernel, david, wangkefeng.wang On Mon, Jun 06, 2022 at 09:34:13AM +0800, Chen Wandun wrote: > On 2022/6/5 19:49, Matthew Wilcox wrote: > > On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote: > > > It will result in null pointer access if shmem_init_inodecache fail, > > > so check return value of shmem_init_inodecache > > You ignored my suggestion from v1. Here, let me write it out for you. > Hi Matthew, > I didn't ignore your suggestion, some explanation is needed, sorry for > that. > > In V1, Kefeng point: > "kmem_cache_create return a pointer to the cache on success, NULL on > failure, > so error = -ENOMEM; is right :)" > > so, I look some similar code such as init_inodecache in kinds of file > system, they all > return -ENOMEM on failure, so is it OK to return -ENOMEM on failure :) > > Besides, kmem_cache_create return NULL on failure, maybe returning error > code > on failure is more proper, but it is another job. I literally wrote out what I think you should do instead. Stop arguing. > > +static int shmem_init_inodecache(void) > > { > > shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", > > sizeof(struct shmem_inode_info), > > 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); > > + if (!shmem_inode_cachep) > > + return -ENOMEM; > > + return 0; > > } > > > > ... > > > > + error = shmem_init_inodecache(); > > + if (error) > > + goto out2; > > > > > > . > ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache 2022-06-06 2:08 ` Matthew Wilcox @ 2022-06-06 2:58 ` Chen Wandun 0 siblings, 0 replies; 8+ messages in thread From: Chen Wandun @ 2022-06-06 2:58 UTC (permalink / raw) To: Matthew Wilcox Cc: hughd, akpm, linux-mm, linux-kernel, david, wangkefeng.wang 在 2022/6/6 10:08, Matthew Wilcox 写道: > On Mon, Jun 06, 2022 at 09:34:13AM +0800, Chen Wandun wrote: >> On 2022/6/5 19:49, Matthew Wilcox wrote: >>> On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote: >>>> It will result in null pointer access if shmem_init_inodecache fail, >>>> so check return value of shmem_init_inodecache >>> You ignored my suggestion from v1. Here, let me write it out for you. >> Hi Matthew, >> I didn't ignore your suggestion, some explanation is needed, sorry for >> that. >> >> In V1, Kefeng point: >> "kmem_cache_create return a pointer to the cache on success, NULL on >> failure, >> so error = -ENOMEM; is right :)" >> >> so, I look some similar code such as init_inodecache in kinds of file >> system, they all >> return -ENOMEM on failure, so is it OK to return -ENOMEM on failure :) >> >> Besides, kmem_cache_create return NULL on failure, maybe returning error >> code >> on failure is more proper, but it is another job. > I literally wrote out what I think you should do instead. Stop arguing. > >>> +static int shmem_init_inodecache(void) >>> { >>> shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", >>> sizeof(struct shmem_inode_info), >>> 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); >>> + if (!shmem_inode_cachep) >>> + return -ENOMEM; >>> + return 0; >>> } >>> >>> ... >>> >>> + error = shmem_init_inodecache(); >>> + if (error) >>> + goto out2; Oh, I misunderstood what you said, feel so sorry. I will send a new version. Thanks. >>> >>> >>> . > . ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr 2022-06-05 3:55 [PATCH v2 0/3] a few cleanup and bugfixes about shmem Chen Wandun 2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun @ 2022-06-05 3:55 ` Chen Wandun 2022-06-05 3:55 ` [PATCH v2 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area Chen Wandun 2 siblings, 0 replies; 8+ messages in thread From: Chen Wandun @ 2022-06-05 3:55 UTC (permalink / raw) To: hughd, akpm, linux-mm, linux-kernel, willy, david, wangkefeng.wang Return error code directly for addr is not PAGE_SIZE aligned or beyond TASK_SIZE, no need to check these cases in caller. Signed-off-by: Chen Wandun <chenwandun@huawei.com> --- mm/shmem.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 17f8297ece29..5e61692f2d8e 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2142,10 +2142,10 @@ unsigned long shmem_get_unmapped_area(struct file *file, return addr; if (IS_ERR_VALUE(addr)) return addr; - if (addr & ~PAGE_MASK) - return addr; + if (offset_in_page(addr)) + return -EINVAL; if (addr > TASK_SIZE - len) - return addr; + return -ENOMEM; if (shmem_huge == SHMEM_HUGE_DENY) return addr; @@ -2196,7 +2196,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, inflated_addr = get_area(NULL, uaddr, inflated_len, 0, flags); if (IS_ERR_VALUE(inflated_addr)) return addr; - if (inflated_addr & ~PAGE_MASK) + if (offset_in_page(inflated_addr)) return addr; inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1); -- 2.25.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area 2022-06-05 3:55 [PATCH v2 0/3] a few cleanup and bugfixes about shmem Chen Wandun 2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun 2022-06-05 3:55 ` [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr Chen Wandun @ 2022-06-05 3:55 ` Chen Wandun 2 siblings, 0 replies; 8+ messages in thread From: Chen Wandun @ 2022-06-05 3:55 UTC (permalink / raw) To: hughd, akpm, linux-mm, linux-kernel, willy, david, wangkefeng.wang In function shmem_get_unmapped_area, inflated_offset and offset are unsigned long, it will result in underflow when offset below inflated_offset, a little confusing, no functional change. Signed-off-by: Chen Wandun <chenwandun@huawei.com> --- mm/shmem.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 5e61692f2d8e..0b6c61a7cbb3 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2200,9 +2200,12 @@ unsigned long shmem_get_unmapped_area(struct file *file, return addr; inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1); - inflated_addr += offset - inflated_offset; - if (inflated_offset > offset) + if (offset > inflated_offset) + inflated_addr += offset - inflated_offset; + else if (offset < inflated_offset) { + inflated_addr -= inflated_offset - offset; inflated_addr += HPAGE_PMD_SIZE; + } if (inflated_addr > TASK_SIZE - len) return addr; -- 2.25.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-06-06 2:59 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-06-05 3:55 [PATCH v2 0/3] a few cleanup and bugfixes about shmem Chen Wandun 2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun 2022-06-05 11:49 ` Matthew Wilcox 2022-06-06 1:34 ` Chen Wandun 2022-06-06 2:08 ` Matthew Wilcox 2022-06-06 2:58 ` Chen Wandun 2022-06-05 3:55 ` [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr Chen Wandun 2022-06-05 3:55 ` [PATCH v2 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area Chen Wandun
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