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author | David Sterba <dsterba@suse.com> | 2021-10-27 11:42:27 +0300 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2021-10-29 14:02:50 +0300 |
commit | 56ee254d23c59fd48fb6f192d79858f60cfe2bf6 (patch) | |
tree | 495c70809215532099d4cf461297cb246ee3f49e /fs/btrfs | |
parent | 3a60f6537c9adf0828bf1dd868c59f659395257e (diff) | |
download | linux-56ee254d23c59fd48fb6f192d79858f60cfe2bf6.tar.xz |
Revert "btrfs: compression: drop kmap/kunmap from zstd"
This reverts commit bbaf9715f3f5b5ff0de71da91fcc34ee9c198ed8.
The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.
Example stacktrace with ZSTD on a 32bit ARM machine:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c4159ed3
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 210 Comm: kworker/u2:3 Not tainted 5.14.0-rc79+ #12
Hardware name: Allwinner sun4i/sun5i Families
Workqueue: btrfs-delalloc btrfs_work_helper
PC is at mmiocpy+0x48/0x330
LR is at ZSTD_compressStream_generic+0x15c/0x28c
(mmiocpy) from [<c0629648>] (ZSTD_compressStream_generic+0x15c/0x28c)
(ZSTD_compressStream_generic) from [<c06297dc>] (ZSTD_compressStream+0x64/0xa0)
(ZSTD_compressStream) from [<c049444c>] (zstd_compress_pages+0x170/0x488)
(zstd_compress_pages) from [<c0496798>] (btrfs_compress_pages+0x124/0x12c)
(btrfs_compress_pages) from [<c043c068>] (compress_file_range+0x3c0/0x834)
(compress_file_range) from [<c043c4ec>] (async_cow_start+0x10/0x28)
(async_cow_start) from [<c0475c3c>] (btrfs_work_helper+0x100/0x230)
(btrfs_work_helper) from [<c014ef68>] (process_one_work+0x1b4/0x418)
(process_one_work) from [<c014f210>] (worker_thread+0x44/0x524)
(worker_thread) from [<c0156aa4>] (kthread+0x180/0x1b0)
(kthread) from [<c0100150>]
Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r-- | fs/btrfs/zstd.c | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c index 56dce9f00988..f06b68040352 100644 --- a/fs/btrfs/zstd.c +++ b/fs/btrfs/zstd.c @@ -399,7 +399,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, /* map in the first page of input data */ in_page = find_get_page(mapping, start >> PAGE_SHIFT); - workspace->in_buf.src = page_address(in_page); + workspace->in_buf.src = kmap(in_page); workspace->in_buf.pos = 0; workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE); @@ -411,7 +411,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, goto out; } pages[nr_pages++] = out_page; - workspace->out_buf.dst = page_address(out_page); + workspace->out_buf.dst = kmap(out_page); workspace->out_buf.pos = 0; workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE); @@ -446,6 +446,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, if (workspace->out_buf.pos == workspace->out_buf.size) { tot_out += PAGE_SIZE; max_out -= PAGE_SIZE; + kunmap(out_page); if (nr_pages == nr_dest_pages) { out_page = NULL; ret = -E2BIG; @@ -457,7 +458,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, goto out; } pages[nr_pages++] = out_page; - workspace->out_buf.dst = page_address(out_page); + workspace->out_buf.dst = kmap(out_page); workspace->out_buf.pos = 0; workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE); @@ -472,12 +473,13 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, /* Check if we need more input */ if (workspace->in_buf.pos == workspace->in_buf.size) { tot_in += PAGE_SIZE; + kunmap(in_page); put_page(in_page); start += PAGE_SIZE; len -= PAGE_SIZE; in_page = find_get_page(mapping, start >> PAGE_SHIFT); - workspace->in_buf.src = page_address(in_page); + workspace->in_buf.src = kmap(in_page); workspace->in_buf.pos = 0; workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE); } @@ -504,6 +506,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, tot_out += PAGE_SIZE; max_out -= PAGE_SIZE; + kunmap(out_page); if (nr_pages == nr_dest_pages) { out_page = NULL; ret = -E2BIG; @@ -515,7 +518,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, goto out; } pages[nr_pages++] = out_page; - workspace->out_buf.dst = page_address(out_page); + workspace->out_buf.dst = kmap(out_page); workspace->out_buf.pos = 0; workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE); } @@ -531,8 +534,12 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, out: *out_pages = nr_pages; /* Cleanup */ - if (in_page) + if (in_page) { + kunmap(in_page); put_page(in_page); + } + if (out_page) + kunmap(out_page); return ret; } @@ -556,7 +563,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) goto done; } - workspace->in_buf.src = page_address(pages_in[page_in_index]); + workspace->in_buf.src = kmap(pages_in[page_in_index]); workspace->in_buf.pos = 0; workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE); @@ -592,14 +599,14 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) break; if (workspace->in_buf.pos == workspace->in_buf.size) { - page_in_index++; + kunmap(pages_in[page_in_index++]); if (page_in_index >= total_pages_in) { workspace->in_buf.src = NULL; ret = -EIO; goto done; } srclen -= PAGE_SIZE; - workspace->in_buf.src = page_address(pages_in[page_in_index]); + workspace->in_buf.src = kmap(pages_in[page_in_index]); workspace->in_buf.pos = 0; workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE); } @@ -607,6 +614,8 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) ret = 0; zero_fill_bio(cb->orig_bio); done: + if (workspace->in_buf.src) + kunmap(pages_in[page_in_index]); return ret; } |