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squashfs: don't call kmalloc in decompressors

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The decompressors may be called while in an atomic section.  So move the
kmalloc() out of this path, and into the "page actor" init function.

This fixes a regression introduced by commit
f268eedddf ("squashfs: extend "page actor" to handle missing pages")

Link: https://lkml.kernel.org/r/20220822215430.15933-1-phillip@squashfs.org.uk
Fixes: f268eedddf ("squashfs: extend "page actor" to handle missing pages")
Reported-by: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Phillip Lougher 2022-08-22 22:54:30 +01:00 committed by Andrew Morton
parent d26f607036
commit 1f13dff09f
4 changed files with 22 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/squashfs/file.c
View File

@ -593,7 +593,7 @@ static void squashfs_readahead(struct readahead_control *ractl)
res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
kfree(actor);
squashfs_page_actor_free(actor);
if (res == expected) {
int bytes;

2
fs/squashfs/file_direct.c
View File

@ -74,7 +74,7 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
/* Decompress directly into the page cache buffers */
res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
kfree(actor);
squashfs_page_actor_free(actor);
if (res < 0)
goto mark_errored;

34
fs/squashfs/page_actor.c
View File

@ -52,6 +52,7 @@ struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
actor->buffer = buffer;
actor->pages = pages;
actor->next_page = 0;
actor->tmp_buffer = NULL;
actor->squashfs_first_page = cache_first_page;
actor->squashfs_next_page = cache_next_page;
actor->squashfs_finish_page = cache_finish_page;
@ -68,20 +69,9 @@ static void *handle_next_page(struct squashfs_page_actor *actor)
if ((actor->next_page == actor->pages) ||
(actor->next_index != actor->page[actor->next_page]->index)) {
if (actor->alloc_buffer) {
void *tmp_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (tmp_buffer) {
actor->tmp_buffer = tmp_buffer;
actor->next_index++;
actor->returned_pages++;
return tmp_buffer;
}
}
actor->next_index++;
actor->returned_pages++;
return ERR_PTR(-ENOMEM);
return actor->alloc_buffer ? actor->tmp_buffer : ERR_PTR(-ENOMEM);
}
actor->next_index++;
@ -96,11 +86,10 @@ static void *direct_first_page(struct squashfs_page_actor *actor)
static void *direct_next_page(struct squashfs_page_actor *actor)
{
if (actor->pageaddr)
if (actor->pageaddr) {
kunmap_local(actor->pageaddr);
kfree(actor->tmp_buffer);
actor->pageaddr = actor->tmp_buffer = NULL;
actor->pageaddr = NULL;
}
return handle_next_page(actor);
}
@ -109,8 +98,6 @@ static void direct_finish_page(struct squashfs_page_actor *actor)
{
if (actor->pageaddr)
kunmap_local(actor->pageaddr);
kfree(actor->tmp_buffer);
}
struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_info *msblk,
@ -121,6 +108,16 @@ struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_
if (actor == NULL)
return NULL;
if (msblk->decompressor->alloc_buffer) {
actor->tmp_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (actor->tmp_buffer == NULL) {
kfree(actor);
return NULL;
}
} else
actor->tmp_buffer = NULL;
actor->length = length ? : pages * PAGE_SIZE;
actor->page = page;
actor->pages = pages;
@ -128,7 +125,6 @@ struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_
actor->returned_pages = 0;
actor->next_index = page[0]->index & ~((1 << (msblk->block_log - PAGE_SHIFT)) - 1);
actor->pageaddr = NULL;
actor->tmp_buffer = NULL;
actor->alloc_buffer = msblk->decompressor->alloc_buffer;
actor->squashfs_first_page = direct_first_page;
actor->squashfs_next_page = direct_next_page;

5
fs/squashfs/page_actor.h
View File

@ -29,6 +29,11 @@ extern struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
extern struct squashfs_page_actor *squashfs_page_actor_init_special(
struct squashfs_sb_info *msblk,
struct page **page, int pages, int length);
static inline void squashfs_page_actor_free(struct squashfs_page_actor *actor)
{
kfree(actor->tmp_buffer);
kfree(actor);
}
static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
{
return actor->squashfs_first_page(actor);