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Sun, 26 Oct 2025 02:14:06 -0700 (PDT) Received: from localhost.localdomain ([124.77.218.104]) by smtp.googlemail.com with ESMTPSA id 98e67ed59e1d1-33fed739b81sm4732043a91.6.2025.10.26.02.14.04 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sun, 26 Oct 2025 02:14:06 -0700 (PDT) From: Miaoqian Lin To: Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: linmq006@gmail.com, stable@vger.kernel.org Subject: [PATCH] s390/mm: Fix memory leak in add_marker() when kvrealloc fails Date: Sun, 26 Oct 2025 17:13:51 +0800 Message-Id: <20251026091351.36275-1-linmq006@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When kvrealloc() fails, the original markers memory is leaked because the function directly assigns the NULL to the markers pointer, losing the reference to the original memory. As a result, the kvfree() in pt_dump_init() ends up freeing NULL instead of the previously allocated memory. Fix this by using a temporary variable to store kvrealloc()'s return value and only update the markers pointer on success. Found via static anlaysis and this is similar to commit 42378a9ca553 ("bpf, verifier: Fix memory leak in array reallocation for stack state") Fixes: d0e7915d2ad3 ("s390/mm/ptdump: Generate address marker array dynamically") Cc: stable@vger.kernel.org Signed-off-by: Miaoqian Lin --- arch/s390/mm/dump_pagetables.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c index 9af2aae0a515..0f2e0c93a1e0 100644 --- a/arch/s390/mm/dump_pagetables.c +++ b/arch/s390/mm/dump_pagetables.c @@ -291,16 +291,19 @@ static int ptdump_cmp(const void *a, const void *b) static int add_marker(unsigned long start, unsigned long end, const char *name) { + struct addr_marker *new_markers; size_t oldsize, newsize; oldsize = markers_cnt * sizeof(*markers); newsize = oldsize + 2 * sizeof(*markers); if (!oldsize) - markers = kvmalloc(newsize, GFP_KERNEL); + new_markers = kvmalloc(newsize, GFP_KERNEL); else - markers = kvrealloc(markers, newsize, GFP_KERNEL); - if (!markers) + new_markers = kvrealloc(markers, newsize, GFP_KERNEL); + if (!new_markers) goto error; + + markers = new_markers; markers[markers_cnt].is_start = 1; markers[markers_cnt].start_address = start; markers[markers_cnt].size = end - start; -- 2.39.5 (Apple Git-154)