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authorDavid Sterba <dsterba@suse.com>2021-10-27 11:42:27 +0300
committerDavid Sterba <dsterba@suse.com>2021-10-29 14:02:50 +0300
commit56ee254d23c59fd48fb6f192d79858f60cfe2bf6 (patch)
tree495c70809215532099d4cf461297cb246ee3f49e /fs
parent3a60f6537c9adf0828bf1dd868c59f659395257e (diff)
downloadlinux-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')
-rw-r--r--fs/btrfs/zstd.c27
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;
}