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b=Dh1NQMIeos18mmb6bY+28BAts5KBo82AirvGqy2ye0JnT9SGtElTW1I6jeyw/4LYD 8D4GTjmGepTrj95fC/S+Po6xpfZva+HtuP+knmg0CntC7w6/AIURe7D/DlN3Y7T+Xh xvE9FMl81Ce+6GO3vky2ZBPVaibFhYqshISvcnA2AC6KL8ujXnknLXMHw2Xo7lnwpp Eo4wIgniW4hC942CH9k+pq68ZLY/0gRFdsWRXtv18Yqo4lHk5wNOhv3UKsWylPVHI+ D88xhZDquGL/6TESiVBoeMfX4VZVwHEoIbIAusdOlB1y7HIbrOL/y/Ln+b+5xKMtEu 8nI1VyiG2czyA== Date: Sat, 5 Jul 2025 22:33:51 +0200 From: Alejandro Colomar To: linux-mm@kvack.org, linux-hardening@vger.kernel.org Cc: Alejandro Colomar , Kees Cook , Christopher Bazley , shadow <~hallyn/shadow@lists.sr.ht>, linux-kernel@vger.kernel.org, Andrew Morton , kasan-dev@googlegroups.com, Dmitry Vyukov , Alexander Potapenko , Marco Elver , Christoph Lameter , David Rientjes , Vlastimil Babka , Roman Gushchin , Harry Yoo Subject: [RFC v1 2/3] stacktrace, stackdepot: Add seprintf()-like variants of functions Message-ID: X-Mailer: git-send-email 2.50.0 References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: AB92B100004 X-Rspam-User: X-Stat-Signature: of4rmsf6yyofci4uijoep1wditpj86sx X-HE-Tag: 1751747634-66260 X-HE-Meta: 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 FhfYuhBG zsfXRf4TACRnfRoNfXjAgMxsHxpXaSG/nUo0LEENSeeavVxYWUhc2C3zSA0vnP45qu/X+Ehbt9Tw76A8i0fO1Dhp+eKhz4c/4mxzPkGQLheZ3BA18fs052NLPvbi2d/PKlDlO1rUuIfZLVjJLWLKZ/UPKqUSZ8pUb9x9OMLAY+zw+mzv769nb8CiPYP/yUaa4V1cIem2LMgPENl2Pd0qotYP5ld3mKeM2b083rRJ9znaBfyNVdVwBk3JzTRV2smxJ8BXuyYHsSYwsmEMcK6UmyzEfLJmSF6q3ey7AYbXhdzW+sBsb5o/APvOa/Ty/RitMT3St5+T/3pvcBg36SEeiaDIk57F/lO2t/gRN5WzK0kO0eVtirKeusLU/ZQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: I think there's an anomaly in stack_depot_s*print(). If we have zero entries, we don't copy anything, which means the string is still not a string. Normally, this function is called surrounded by other calls to s*printf(), which guarantee that there's a '\0', but maybe we should make sure to write a '\0' here? Cc: Kees Cook Cc: Christopher Bazley Signed-off-by: Alejandro Colomar --- include/linux/stackdepot.h | 13 +++++++++++++ include/linux/stacktrace.h | 3 +++ kernel/stacktrace.c | 28 ++++++++++++++++++++++++++++ lib/stackdepot.c | 12 ++++++++++++ 4 files changed, 56 insertions(+) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 2cc21ffcdaf9..a7749fc3ac7c 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -219,6 +219,19 @@ void stack_depot_print(depot_stack_handle_t stack); int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces); +/** + * stack_depot_seprint - Print a stack trace from stack depot into a buffer + * + * @handle: Stack depot handle returned from stack_depot_save() + * @p: Pointer to the print buffer + * @end: Pointer to one past the last element in the buffer + * @spaces: Number of leading spaces to print + * + * Return: Pointer to trailing '\0'; or NULL on truncation + */ +char *stack_depot_seprint(depot_stack_handle_t handle, char *p, + const char end[0], int spaces); + /** * stack_depot_put - Drop a reference to a stack trace from stack depot * diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h index 97455880ac41..748936386c89 100644 --- a/include/linux/stacktrace.h +++ b/include/linux/stacktrace.h @@ -67,6 +67,9 @@ void stack_trace_print(const unsigned long *trace, unsigned int nr_entries, int spaces); int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries, unsigned int nr_entries, int spaces); +char *stack_trace_seprint(char *p, const char end[0], + const unsigned long *entries, unsigned int nr_entries, + int spaces); unsigned int stack_trace_save(unsigned long *store, unsigned int size, unsigned int skipnr); unsigned int stack_trace_save_tsk(struct task_struct *task, diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index afb3c116da91..65caf9e63673 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -70,6 +70,34 @@ int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries, } EXPORT_SYMBOL_GPL(stack_trace_snprint); +/** + * stack_trace_seprint - Print the entries in the stack trace into a buffer + * @p: Pointer to the print buffer + * @end: Pointer to one past the last element in the buffer + * @entries: Pointer to storage array + * @nr_entries: Number of entries in the storage array + * @spaces: Number of leading spaces to print + * + * Return: Pointer to the trailing '\0'; or NULL on truncation. + */ +char *stack_trace_seprint(char *p, const char end[0], + const unsigned long *entries, unsigned int nr_entries, + int spaces) +{ + unsigned int i; + + if (WARN_ON(!entries)) + return 0; + + for (i = 0; i < nr_entries; i++) { + p = seprintf(p, end, "%*c%pS\n", 1 + spaces, ' ', + (void *)entries[i]); + } + + return p; +} +EXPORT_SYMBOL_GPL(stack_trace_seprint); + #ifdef CONFIG_ARCH_STACKWALK struct stacktrace_cookie { diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 73d7b50924ef..a61903040724 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -771,6 +771,18 @@ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, } EXPORT_SYMBOL_GPL(stack_depot_snprint); +char *stack_depot_seprint(depot_stack_handle_t handle, char *p, + const char end[0], int spaces) +{ + unsigned long *entries; + unsigned int nr_entries; + + nr_entries = stack_depot_fetch(handle, &entries); + return nr_entries ? stack_trace_seprint(p, e, entries, nr_entries, + spaces) : p; +} +EXPORT_SYMBOL_GPL(stack_depot_seprint); + depot_stack_handle_t __must_check stack_depot_set_extra_bits( depot_stack_handle_t handle, unsigned int extra_bits) { -- 2.50.0