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[82.37.195.13]) by smtp.gmail.com with ESMTPSA id bh6-20020a05600c3d0600b0040b54335d57sm17055244wmb.17.2023.12.06.03.37.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Dec 2023 03:37:55 -0800 (PST) Date: Wed, 6 Dec 2023 11:37:53 +0000 From: Daniel Thompson To: Doug Anderson Cc: Yuran Pereira , kgdb-bugreport@lists.sourceforge.net, linux-trace-kernel@vger.kernel.org, jason.wessel@windriver.com, rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [PATCH 2/2] trace: kdb: Replace simple_strtoul with kstrtoul in kdb_ftdump Message-ID: <20231206113753.GB81045@aspen.lan> References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, Dec 05, 2023 at 01:41:57PM -0800, Doug Anderson wrote: > Hi, > > On Sun, Nov 19, 2023 at 4:10 PM Yuran Pereira wrote: > > > > The function simple_strtoul performs no error checking in scenarios > > where the input value overflows the intended output variable. > > This results in this function successfully returning, even when the > > output does not match the input string (aka the function returns > > successfully even when the result is wrong). > > > > Or as it was mentioned [1], "...simple_strtol(), simple_strtoll(), > > simple_strtoul(), and simple_strtoull() functions explicitly ignore > > overflows, which may lead to unexpected results in callers." > > Hence, the use of those functions is discouraged. > > > > This patch replaces all uses of the simple_strtoul with the safer > > alternatives kstrtoint and kstrtol. > > > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#simple-strtol-simple-strtoll-simple-strtoul-simple-strtoull > > > > Signed-off-by: Yuran Pereira > > --- > > kernel/trace/trace_kdb.c | 14 ++++++-------- > > 1 file changed, 6 insertions(+), 8 deletions(-) > > > > diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c > > index 59857a1ee44c..3891f885e4a6 100644 > > --- a/kernel/trace/trace_kdb.c > > +++ b/kernel/trace/trace_kdb.c > > @@ -96,23 +96,21 @@ static int kdb_ftdump(int argc, const char **argv) > > { > > int skip_entries = 0; > > long cpu_file; > > - char *cp; > > + int err; > > int cnt; > > int cpu; > > > > if (argc > 2) > > return KDB_ARGCOUNT; > > > > - if (argc) { > > - skip_entries = simple_strtol(argv[1], &cp, 0); > > - if (*cp) > > + if (argc) > > + if (kstrtoint(argv[1], 0, &skip_entries)) > > skip_entries = 0; > > - } > > Similar nit about braces as in patch #1. tl;dr is change the above to: > > if (argc && kstrtoint(argv[1], 0, &skip_entries)) > skip_entries = 0; Surely that should be: if (...) return KDB_BADINT; There seems little point switching to a "safer" API if we just ignore the errors it provides us. Daniel.