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| author | Giovanni Cabiddu <giovanni.cabiddu@intel.com> | 2025-11-20 16:26:09 +0000 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2025-12-01 18:05:07 +0800 |
| commit | 48bc9da3c97c15f1ea24934bcb3b736acd30163d (patch) | |
| tree | 289291cb75301c8761e9c0ba90ddd65fa8d0f9c6 /crypto/zstd.c | |
| parent | ebbdf6466b30e3b37f3b360826efd21f0633fb9e (diff) | |
| download | net-48bc9da3c97c15f1ea24934bcb3b736acd30163d.tar.gz | |
crypto: zstd - fix double-free in per-CPU stream cleanup
The crypto/zstd module has a double-free bug that occurs when multiple
tfms are allocated and freed.
The issue happens because zstd_streams (per-CPU contexts) are freed in
zstd_exit() during every tfm destruction, rather than being managed at
the module level. When multiple tfms exist, each tfm exit attempts to
free the same shared per-CPU streams, resulting in a double-free.
This leads to a stack trace similar to:
BUG: Bad page state in process kworker/u16:1 pfn:106fd93
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106fd93
flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
page_type: 0xffffffff()
raw: 0017ffffc0000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: nonzero entire_mapcount
Modules linked in: ...
CPU: 3 UID: 0 PID: 2506 Comm: kworker/u16:1 Kdump: loaded Tainted: G B
Hardware name: ...
Workqueue: btrfs-delalloc btrfs_work_helper
Call Trace:
<TASK>
dump_stack_lvl+0x5d/0x80
bad_page+0x71/0xd0
free_unref_page_prepare+0x24e/0x490
free_unref_page+0x60/0x170
crypto_acomp_free_streams+0x5d/0xc0
crypto_acomp_exit_tfm+0x23/0x50
crypto_destroy_tfm+0x60/0xc0
...
Change the lifecycle management of zstd_streams to free the streams only
once during module cleanup.
Fixes: f5ad93ffb541 ("crypto: zstd - convert to acomp")
Cc: stable@vger.kernel.org
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Suman Kumar Chakraborty <suman.kumar.chakraborty@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/zstd.c')
| -rw-r--r-- | crypto/zstd.c | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/crypto/zstd.c b/crypto/zstd.c index dc5b36141ff8a8..cbbd0413751aea 100644 --- a/crypto/zstd.c +++ b/crypto/zstd.c @@ -75,11 +75,6 @@ static int zstd_init(struct crypto_acomp *acomp_tfm) return ret; } -static void zstd_exit(struct crypto_acomp *acomp_tfm) -{ - crypto_acomp_free_streams(&zstd_streams); -} - static int zstd_compress_one(struct acomp_req *req, struct zstd_ctx *ctx, const void *src, void *dst, unsigned int *dlen) { @@ -297,7 +292,6 @@ static struct acomp_alg zstd_acomp = { .cra_module = THIS_MODULE, }, .init = zstd_init, - .exit = zstd_exit, .compress = zstd_compress, .decompress = zstd_decompress, }; @@ -310,6 +304,7 @@ static int __init zstd_mod_init(void) static void __exit zstd_mod_fini(void) { crypto_unregister_acomp(&zstd_acomp); + crypto_acomp_free_streams(&zstd_streams); } module_init(zstd_mod_init); |