The patch titled
Subject: squashfs: don't call kmalloc in decompressors
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
squashfs-dont-call-kmalloc-in-decompressors.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/squashfs-dont-call-kmalloc-in-decompressors.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
Subject: squashfs: don't call kmalloc in decompressors
Date: Mon, 22 Aug 2022 22:54:30 +0100
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
f268eedddf35 ("squashfs: extend "page actor" to handle missing pages")
Link: https://lkml.kernel.org/r/20220822215430.15933-1-phillip@xxxxxxxxxxxxxxx
Fixes: f268eedddf35 ("squashfs: extend "page actor" to handle missing pages")
Reported-by: Chris Murphy <lists@xxxxxxxxxxxxxxxxx>
Signed-off-by: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/squashfs/file.c | 2 +-
fs/squashfs/file_direct.c | 2 +-
fs/squashfs/page_actor.c | 34 +++++++++++++++-------------------
fs/squashfs/page_actor.h | 5 +++++
4 files changed, 22 insertions(+), 21 deletions(-)
--- a/fs/squashfs/file.c~squashfs-dont-call-kmalloc-in-decompressors
+++ a/fs/squashfs/file.c
@@ -593,7 +593,7 @@ static void squashfs_readahead(struct re
res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
- kfree(actor);
+ squashfs_page_actor_free(actor);
if (res == expected) {
int bytes;
--- a/fs/squashfs/file_direct.c~squashfs-dont-call-kmalloc-in-decompressors
+++ a/fs/squashfs/file_direct.c
@@ -74,7 +74,7 @@ int squashfs_readpage_block(struct page
/* 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;
--- a/fs/squashfs/page_actor.c~squashfs-dont-call-kmalloc-in-decompressors
+++ a/fs/squashfs/page_actor.c
@@ -52,6 +52,7 @@ struct squashfs_page_actor *squashfs_pag
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 squ
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 sq
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 sq
{
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_pag
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_pag
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;
--- a/fs/squashfs/page_actor.h~squashfs-dont-call-kmalloc-in-decompressors
+++ a/fs/squashfs/page_actor.h
@@ -29,6 +29,11 @@ extern struct squashfs_page_actor *squas
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);
_
Patches currently in -mm which might be from phillip@xxxxxxxxxxxxxxx are
squashfs-dont-call-kmalloc-in-decompressors.patch
