PM: hibernate: Fix crash when freeing invalid crypto compressor

When crypto_alloc_acomp() fails, it returns an ERR_PTR value, not NULL.

The cleanup code in save_compressed_image() and load_compressed_image()
unconditionally calls crypto_free_acomp() without checking for ERR_PTR,
which causes crypto_acomp_tfm() to dereference an invalid pointer and
crash the kernel.

This can be triggered when the compression algorithm is unavailable
(e.g., CONFIG_CRYPTO_LZO not enabled).

Fix by adding IS_ERR_OR_NULL() checks before calling crypto_free_acomp()
and acomp_request_free(), similar to the existing kthread_stop() check.

Fixes: b03d542c3c95 ("PM: hibernate: Use crypto_acomp interface")
Signed-off-by: Malaya Kumar Rout <mrout@redhat.com>
Cc: 6.15+ <stable@vger.kernel.org> # 6.15+
[ rjw: Added 2 empty code lines ]
Link: https://patch.msgid.link/20251230115613.64080-1-mrout@redhat.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 33a186373bef23e2329f1dea05d2c6dc709c46ed..8050e5182835166a047f4a46078c448f9787083c 100644 (file)
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -902,8 +902,11 @@ out_clean:
                for (thr = 0; thr < nr_threads; thr++) {
                        if (data[thr].thr)
                                kthread_stop(data[thr].thr);
-                       acomp_request_free(data[thr].cr);
-                       crypto_free_acomp(data[thr].cc);
+                       if (data[thr].cr)
+                               acomp_request_free(data[thr].cr);
+
+                       if (!IS_ERR_OR_NULL(data[thr].cc))
+                               crypto_free_acomp(data[thr].cc);
                }
                vfree(data);
        }
@@ -1499,8 +1502,11 @@ out_clean:
                for (thr = 0; thr < nr_threads; thr++) {
                        if (data[thr].thr)
                                kthread_stop(data[thr].thr);
-                       acomp_request_free(data[thr].cr);
-                       crypto_free_acomp(data[thr].cc);
+                       if (data[thr].cr)
+                               acomp_request_free(data[thr].cr);
+
+                       if (!IS_ERR_OR_NULL(data[thr].cc))
+                               crypto_free_acomp(data[thr].cc);
                }
                vfree(data);
        }