Messages in this thread | | | Date | Thu, 20 Oct 2022 20:02:02 +0700 | Subject | Re: BISECT result: 6.0.0-RC kernels trigger Firefox snap bug with 6.0.0-rc3 through 6.0.0-rc7 | From | Bagas Sanjaya <> |
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On 10/20/22 14:43, Jintao Yin wrote: > Ignore my before diff. I didn't notice the end_index caculation greater > than file_end part. Use the following diff instead. > > This diff is based on Phillip's latest two patches and improves the logic > to update the status of pages only if page actor touches them. > > Please help test and feedbacks are welcome. > > Thanks, > > Jintao > > diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c > index e56510964b22..5efa2a9f9630 100644 > --- a/fs/squashfs/file.c > +++ b/fs/squashfs/file.c > @@ -506,8 +506,9 @@ static int squashfs_readahead_fragment(struct page **page, > squashfs_i(inode)->fragment_size); > struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info; > unsigned int n, mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1; > + int res = buffer->error; > > - if (buffer->error) > + if (res) > goto out; > > expected += squashfs_i(inode)->fragment_offset; > @@ -529,7 +530,7 @@ static int squashfs_readahead_fragment(struct page **page, > > out: > squashfs_cache_put(buffer); > - return buffer->error; > + return res; > } > > static void squashfs_readahead(struct readahead_control *ractl) > @@ -557,6 +558,7 @@ static void squashfs_readahead(struct readahead_control *ractl) > int res, bsize; > u64 block = 0; > unsigned int expected; > + int nr_used_pages; > > nr_pages = __readahead_batch(ractl, pages, max_pages); > if (!nr_pages) > @@ -593,18 +595,18 @@ static void squashfs_readahead(struct readahead_control *ractl) > > res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor); > > - squashfs_page_actor_free(actor); > + nr_used_pages = squashfs_page_actor_free(actor); > > if (res == expected) { > int bytes; > > /* Last page (if present) may have trailing bytes not filled */ > bytes = res % PAGE_SIZE; > - if (pages[nr_pages - 1]->index == file_end && bytes) > - memzero_page(pages[nr_pages - 1], bytes, > + if (index == file_end && bytes && nr_used_pages > 0) > + memzero_page(pages[nr_used_pages - 1], bytes, > PAGE_SIZE - bytes); > > - for (i = 0; i < nr_pages; i++) { > + for (i = 0; i < nr_used_pages; i++) { > flush_dcache_page(pages[i]); > SetPageUptodate(pages[i]); > } > diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c > index f1ccad519e28..1bb0347f98b0 100644 > --- a/fs/squashfs/file_direct.c > +++ b/fs/squashfs/file_direct.c > @@ -30,10 +30,9 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, > int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1; > int start_index = target_page->index & ~mask; > int end_index = start_index | mask; > - int i, n, pages, bytes, res = -ENOMEM; > + int i, n, pages, used_pages, bytes, res = -ENOMEM; > struct page **page; > struct squashfs_page_actor *actor; > - void *pageaddr; > > if (end_index > file_end) > end_index = file_end; > @@ -74,7 +73,7 @@ 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); > > - squashfs_page_actor_free(actor); > + used_pages = squashfs_page_actor_free(actor); > > if (res < 0) > goto mark_errored; > @@ -86,16 +85,18 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, > > /* Last page (if present) may have trailing bytes not filled */ > bytes = res % PAGE_SIZE; > - if (page[pages - 1]->index == end_index && bytes) { > - pageaddr = kmap_local_page(page[pages - 1]); > - memset(pageaddr + bytes, 0, PAGE_SIZE - bytes); > - kunmap_local(pageaddr); > + if (used_pages > 0 && page[used_pages - 1]->index == end_index && > + bytes) { > + memzero_page(page[used_pages - 1], bytes, > + PAGE_SIZE - bytes); > } > > /* Mark pages as uptodate, unlock and release */ > for (i = 0; i < pages; i++) { > - flush_dcache_page(page[i]); > - SetPageUptodate(page[i]); > + if (i < used_pages) { > + flush_dcache_page(page[i]); > + SetPageUptodate(page[i]); > + } > unlock_page(page[i]); > if (page[i] != target_page) > put_page(page[i]); > @@ -112,8 +113,10 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, > for (i = 0; i < pages; i++) { > if (page[i] == NULL || page[i] == target_page) > continue; > - flush_dcache_page(page[i]); > - SetPageError(page[i]); > + if (i < used_pages) { > + flush_dcache_page(page[i]); > + SetPageError(page[i]); > + } > unlock_page(page[i]); > put_page(page[i]); > } > diff --git a/fs/squashfs/page_actor.h b/fs/squashfs/page_actor.h > index 95ffbb543d91..c2c5c3937ef9 100644 > --- a/fs/squashfs/page_actor.h > +++ b/fs/squashfs/page_actor.h > @@ -29,10 +29,12 @@ 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) > +static inline int squashfs_page_actor_free(struct squashfs_page_actor *actor) > { > + int res = actor->next_page; > kfree(actor->tmp_buffer); > kfree(actor); > + return res; > } > static inline void *squashfs_first_page(struct squashfs_page_actor *actor) > {
Hi Jintao,
Booting v6.1-rc1 with your patch applied, I got mixed results. On hello-world snap, it runs without errors. On lxd, I got the Verneed regression as originally reported. Sometimes I also get snapd panic.
Thanks.
-- An old man doll... just what I always wanted! - Clara
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