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Date: Mon, 22 Jun 2009 09:31:46 +0200 From: Frederic Weisbecker <fweisbec@...il.com> To: "K.Prasad" <prasad@...ux.vnet.ibm.com> Cc: Ingo Molnar <mingo@...e.hu>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: [Patch 2/3] ksym_tracer: Allow bulk removal using empty or wildcard string input On Sat, Jun 20, 2009 at 07:07:52PM +0530, K.Prasad wrote: > On Sat, Jun 20, 2009 at 01:16:41AM +0200, Frederic Weisbecker wrote: > > On Fri, Jun 19, 2009 at 10:55:12PM +0530, K.Prasad wrote: > > > Accept an empty string or wildcard input (of the form *:---) as input for > > > ksym_trace_filter to perform bulk removal of all monitored entries. > > > > > > Signed-off-by: K.Prasad <prasad@...ux.vnet.ibm.com> > > > --- > > > kernel/trace/trace_ksym.c | 75 +++++++++++++++++++++++++--------------------- > > > 1 file changed, 42 insertions(+), 33 deletions(-) > > > > <snipped> > > > /* > > > * There can be several possible malformed requests and we attempt to capture > > > * all of them. We enumerate some of the rules > > > @@ -163,7 +191,7 @@ static int parse_ksym_trace_str(char *in > > > /* Check for malformed request: (2), (1) and (5) */ > > > if ((!input_string) || > > > (strlen(input_string) != (KSYM_TRACER_OP_LEN + 1)) || > > > - (*addr == 0)) > > > + ((*addr == 0) && strncmp(*ksymname, "*", strlen("*")))) > > > > > > I guess you can just use strcmp() here, no? As in other use > > of this same strncmp() in this patch. > > > > I see both functions being used in the kernel at random (what happened > to all the buffer-overflow scare?)! Isn't an strncmp() preferred over > the plain strcmp() (atleast it cannot be the other way round)? I guess it depends if the string has complicated origins :) But a plain 1 for the len would be sufficient. Or here you can just check **ksymname != '*' Anyway, I'm arguing about neat things that don't matter that much. Thanks. > > > @@ -251,9 +280,11 @@ static ssize_t ksym_trace_filter_write(s > > > unsigned long ksym_addr = 0; > > > int ret, op, changed = 0; > > > > > > - /* Ignore echo "" > ksym_trace_filter */ > > > - if (count == 0) > > > - return 0; > > > + /* Clear all breakpoint requests if echo "" > ksym_trace_filter */ > > > + if (count == 1) { > > > + ksym_trace_reset(NULL); > > > + return count; > > > + } > > > > > > And then if I do: > > > > echo -n 1 > ksym_trace_filter > > > > That would also clean these breakpoints? > > > > Frederic. > > > > No, I did not think about this scenario and I am changing the patch to > handle such a case. Also, the value of 'count' cannot be '0' as such > inputs are ignored (e.g. echo -n "" > ksym_trace_filter is simply > ignored) and so I'm removing the check for the same. > > Please find a new version of the patch sent here: > http://lkml.org/lkml/2009/6/20/73. > > Thanks, > K.Prasad > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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