From 1f13dff09ffc8bcf6aa20639b638d813379c7f6b Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Mon, 22 Aug 2022 22:54:30 +0100 Subject: 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/page_actor.c | 34 +++++++++++++++------------------- 1 file changed, 15 insertions(+), 19 deletions(-) (limited to 'fs/squashfs/page_actor.c') diff --git a/fs/squashfs/page_actor.c b/fs/squashfs/page_actor.c index b23b780d8f42..54b93bf4a25c 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; -- cgit v1.2.3