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squashfs: don't call kmalloc in decompressors 

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);