From 1f13dff09ffc8bcf6aa20639b638d813379c7f6b Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Mon, 22 Aug 2022 22:54:30 +0100 Subject: [PATCH] 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 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 Signed-off-by: Phillip Lougher Cc: Signed-off-by: Andrew Morton --- 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(-) diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c index 98e64fec75b77..e56510964b229 100644 --- a/fs/squashfs/file.c +++ b/fs/squashfs/file.c @@ -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; diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c index be4b12d31e0c3..f1ccad519e28c 100644 --- a/fs/squashfs/file_direct.c +++ b/fs/squashfs/file_direct.c @@ -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; diff --git a/fs/squashfs/page_actor.c b/fs/squashfs/page_actor.c index b23b780d8f42e..54b93bf4a25c1 100644 --- a/fs/squashfs/page_actor.c +++ b/fs/squashfs/page_actor.c @@ -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; diff --git a/fs/squashfs/page_actor.h b/fs/squashfs/page_actor.h index 24841d28bc0fb..95ffbb543d913 100644 --- a/fs/squashfs/page_actor.h +++ b/fs/squashfs/page_actor.h @@ -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); -- 2.30.2