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...
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@squashfs.org.uk 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@squashfs.org.uk Fixes: f268eedddf35 ("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 ---
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@squashfs.org.uk are
squashfs-dont-call-kmalloc-in-decompressors.patch