* Re: [PATCH] vl: Fix an assert failure in error path
2021-06-10 8:47 [PATCH] vl: Fix an assert failure in error path Zhenzhong Duan
@ 2021-06-09 9:30 ` Paolo Bonzini
2021-06-09 12:09 ` Markus Armbruster
0 siblings, 1 reply; 8+ messages in thread
From: Paolo Bonzini @ 2021-06-09 9:30 UTC (permalink / raw)
To: Zhenzhong Duan, qemu-devel
On 10/06/21 10:47, Zhenzhong Duan wrote:
> Based on the description of error_setg(), the local variable err in
> qemu_maybe_daemonize() should be initialized to NULL.
>
> Without fix, the uninitialized *errp triggers assert failure which
> doesn't show much valuable information.
>
> Before the fix:
> qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' failed.
>
> After fix:
> qemu-system-x86_64: cannot create PID file: Cannot open pid file: Permission denied
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
> softmmu/vl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/softmmu/vl.c b/softmmu/vl.c
> index 326c1e9080..feb4d201f3 100644
> --- a/softmmu/vl.c
> +++ b/softmmu/vl.c
> @@ -2522,7 +2522,7 @@ static void qemu_process_help_options(void)
>
> static void qemu_maybe_daemonize(const char *pid_file)
> {
> - Error *err;
> + Error *err = NULL;
>
> os_daemonize();
> rcu_disable_atfork();
>
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] vl: Fix an assert failure in error path
2021-06-09 9:30 ` Paolo Bonzini
@ 2021-06-09 12:09 ` Markus Armbruster
2021-06-09 12:15 ` Daniel P. Berrangé
2021-06-10 12:55 ` Paolo Bonzini
0 siblings, 2 replies; 8+ messages in thread
From: Markus Armbruster @ 2021-06-09 12:09 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: Zhenzhong Duan, qemu-devel
Paolo Bonzini <pbonzini@redhat.com> writes:
> On 10/06/21 10:47, Zhenzhong Duan wrote:
>> Based on the description of error_setg(), the local variable err in
>> qemu_maybe_daemonize() should be initialized to NULL.
>> Without fix, the uninitialized *errp triggers assert failure which
>> doesn't show much valuable information.
>> Before the fix:
>> qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' failed.
>> After fix:
>> qemu-system-x86_64: cannot create PID file: Cannot open pid file: Permission denied
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>> softmmu/vl.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> diff --git a/softmmu/vl.c b/softmmu/vl.c
>> index 326c1e9080..feb4d201f3 100644
>> --- a/softmmu/vl.c
>> +++ b/softmmu/vl.c
>> @@ -2522,7 +2522,7 @@ static void qemu_process_help_options(void)
>> static void qemu_maybe_daemonize(const char *pid_file)
>> {
>> - Error *err;
>> + Error *err = NULL;
Common mistake, I'm afraid.
>> os_daemonize();
>> rcu_disable_atfork();
>>
>
> Queued, thanks.
Suggest to amend the commit message with
Fixes: 03d2b412aaf2078425f8472f31c8a9c2340969eb
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] vl: Fix an assert failure in error path
2021-06-09 12:09 ` Markus Armbruster
@ 2021-06-09 12:15 ` Daniel P. Berrangé
2021-06-10 1:47 ` Peng Liang
2021-06-10 12:55 ` Paolo Bonzini
1 sibling, 1 reply; 8+ messages in thread
From: Daniel P. Berrangé @ 2021-06-09 12:15 UTC (permalink / raw)
To: Markus Armbruster; +Cc: Paolo Bonzini, Zhenzhong Duan, qemu-devel
On Wed, Jun 09, 2021 at 02:09:47PM +0200, Markus Armbruster wrote:
> Paolo Bonzini <pbonzini@redhat.com> writes:
>
> > On 10/06/21 10:47, Zhenzhong Duan wrote:
> >> Based on the description of error_setg(), the local variable err in
> >> qemu_maybe_daemonize() should be initialized to NULL.
> >> Without fix, the uninitialized *errp triggers assert failure which
> >> doesn't show much valuable information.
> >> Before the fix:
> >> qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' failed.
> >> After fix:
> >> qemu-system-x86_64: cannot create PID file: Cannot open pid file: Permission denied
> >> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> >> ---
> >> softmmu/vl.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >> diff --git a/softmmu/vl.c b/softmmu/vl.c
> >> index 326c1e9080..feb4d201f3 100644
> >> --- a/softmmu/vl.c
> >> +++ b/softmmu/vl.c
> >> @@ -2522,7 +2522,7 @@ static void qemu_process_help_options(void)
> >> static void qemu_maybe_daemonize(const char *pid_file)
> >> {
> >> - Error *err;
> >> + Error *err = NULL;
>
> Common mistake, I'm afraid.
Initializing isn't likely to be a performance impact, so I'd think
we should make 'checkpatch.pl' complain about any 'Error *' variable
that is not initialized to NULL, as a safety net, even if not technically
required in some cases.
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] vl: Fix an assert failure in error path
2021-06-09 12:15 ` Daniel P. Berrangé
@ 2021-06-10 1:47 ` Peng Liang
2021-06-10 7:32 ` Markus Armbruster
0 siblings, 1 reply; 8+ messages in thread
From: Peng Liang @ 2021-06-10 1:47 UTC (permalink / raw)
To: Daniel P. Berrangé, Markus Armbruster
Cc: Paolo Bonzini, Zhenzhong Duan, qemu-devel
On 6/9/2021 8:15 PM, Daniel P. Berrangé wrote:
> On Wed, Jun 09, 2021 at 02:09:47PM +0200, Markus Armbruster wrote:
>> Paolo Bonzini <pbonzini@redhat.com> writes:
>>
>>> On 10/06/21 10:47, Zhenzhong Duan wrote:
>>>> Based on the description of error_setg(), the local variable err in
>>>> qemu_maybe_daemonize() should be initialized to NULL.
>>>> Without fix, the uninitialized *errp triggers assert failure which
>>>> doesn't show much valuable information.
>>>> Before the fix:
>>>> qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' failed.
>>>> After fix:
>>>> qemu-system-x86_64: cannot create PID file: Cannot open pid file: Permission denied
>>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>>> ---
>>>> softmmu/vl.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>> diff --git a/softmmu/vl.c b/softmmu/vl.c
>>>> index 326c1e9080..feb4d201f3 100644
>>>> --- a/softmmu/vl.c
>>>> +++ b/softmmu/vl.c
>>>> @@ -2522,7 +2522,7 @@ static void qemu_process_help_options(void)
>>>> static void qemu_maybe_daemonize(const char *pid_file)
>>>> {
>>>> - Error *err;
>>>> + Error *err = NULL;
>>
>> Common mistake, I'm afraid.
>
> Initializing isn't likely to be a performance impact, so I'd think
> we should make 'checkpatch.pl' complain about any 'Error *' variable
> that is not initialized to NULL, as a safety net, even if not technically
> required in some cases.
>
> Regards,
> Daniel
>
Hi,
Could we add a coccinelle script to check (and fix) these problems? e.g.:
@ r @
identifier id;
@@
Error *id
+ = NULL
;
Using this script, I found that local variable err in
qemu_init_subsystems is not initialized to NULL too. The script is not
prefect though, it will initialize all global/static 'Error *' variables
and all local 'Error *' variables in util/error.c to NULL, which is
unnecessary.
Thanks,
Peng
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] vl: Fix an assert failure in error path
2021-06-10 1:47 ` Peng Liang
@ 2021-06-10 7:32 ` Markus Armbruster
2021-06-10 13:29 ` Peng Liang
0 siblings, 1 reply; 8+ messages in thread
From: Markus Armbruster @ 2021-06-10 7:32 UTC (permalink / raw)
To: Peng Liang
Cc: Paolo Bonzini, Daniel P. Berrangé, Zhenzhong Duan, qemu-devel
Peng Liang <liangpeng10@huawei.com> writes:
> On 6/9/2021 8:15 PM, Daniel P. Berrangé wrote:
>> On Wed, Jun 09, 2021 at 02:09:47PM +0200, Markus Armbruster wrote:
>>> Paolo Bonzini <pbonzini@redhat.com> writes:
>>>
>>>> On 10/06/21 10:47, Zhenzhong Duan wrote:
>>>>> Based on the description of error_setg(), the local variable err in
>>>>> qemu_maybe_daemonize() should be initialized to NULL.
>>>>> Without fix, the uninitialized *errp triggers assert failure which
>>>>> doesn't show much valuable information.
>>>>> Before the fix:
>>>>> qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' failed.
>>>>> After fix:
>>>>> qemu-system-x86_64: cannot create PID file: Cannot open pid file: Permission denied
>>>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>>>> ---
>>>>> softmmu/vl.c | 2 +-
>>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>> diff --git a/softmmu/vl.c b/softmmu/vl.c
>>>>> index 326c1e9080..feb4d201f3 100644
>>>>> --- a/softmmu/vl.c
>>>>> +++ b/softmmu/vl.c
>>>>> @@ -2522,7 +2522,7 @@ static void qemu_process_help_options(void)
>>>>> static void qemu_maybe_daemonize(const char *pid_file)
>>>>> {
>>>>> - Error *err;
>>>>> + Error *err = NULL;
>>>
>>> Common mistake, I'm afraid.
>>
>> Initializing isn't likely to be a performance impact, so I'd think
>> we should make 'checkpatch.pl' complain about any 'Error *' variable
>> that is not initialized to NULL, as a safety net, even if not technically
>> required in some cases.
>>
>> Regards,
>> Daniel
>>
>
> Hi,
> Could we add a coccinelle script to check (and fix) these problems? e.g.:
Coccinelle is good for finding and fixing instances of bad patterns that
have crept in. checkpatch is good for keeping them out. Both has its
uses.
> @ r @
> identifier id;
> @@
> Error *id
> + = NULL
> ;
>
> Using this script, I found that local variable err in
> qemu_init_subsystems is not initialized to NULL too.
Crash bug, broken in commit efd7ab22fb "vl: extract
qemu_init_subsystems", v6.0.0. Care to submit a fix?
> The script is not
> prefect though, it will initialize all global/static 'Error *' variables
> and all local 'Error *' variables in util/error.c to NULL, which is
> unnecessary.
Excluding util/error.c is easy once you know how to:
@ depends on !(file in "util/error.c")@
identifier id;
@@
...
Excluding variable definitions with static storage duraction shouldn't
be too hard, either. If Coccinelle is sufficiently clever, adding
keyword auto suffices. Else, try matching keyword static separately,
like so:
(
static Error *id;
|
- Error *id;
+ Error *id = NULL;
)
Completely untested.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] vl: Fix an assert failure in error path
@ 2021-06-10 8:47 Zhenzhong Duan
2021-06-09 9:30 ` Paolo Bonzini
0 siblings, 1 reply; 8+ messages in thread
From: Zhenzhong Duan @ 2021-06-10 8:47 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, Zhenzhong Duan
Based on the description of error_setg(), the local variable err in
qemu_maybe_daemonize() should be initialized to NULL.
Without fix, the uninitialized *errp triggers assert failure which
doesn't show much valuable information.
Before the fix:
qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' failed.
After fix:
qemu-system-x86_64: cannot create PID file: Cannot open pid file: Permission denied
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
softmmu/vl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 326c1e9080..feb4d201f3 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2522,7 +2522,7 @@ static void qemu_process_help_options(void)
static void qemu_maybe_daemonize(const char *pid_file)
{
- Error *err;
+ Error *err = NULL;
os_daemonize();
rcu_disable_atfork();
--
2.25.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] vl: Fix an assert failure in error path
2021-06-09 12:09 ` Markus Armbruster
2021-06-09 12:15 ` Daniel P. Berrangé
@ 2021-06-10 12:55 ` Paolo Bonzini
1 sibling, 0 replies; 8+ messages in thread
From: Paolo Bonzini @ 2021-06-10 12:55 UTC (permalink / raw)
To: Markus Armbruster; +Cc: Zhenzhong Duan, qemu-devel
On 09/06/21 14:09, Markus Armbruster wrote:
> Fixes: 03d2b412aaf2078425f8472f31c8a9c2340969eb
Actually 0546c0609c ("vl: split various early command line options to a
separate function", 2020-12-10).
Done, thanks!
Paolo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] vl: Fix an assert failure in error path
2021-06-10 7:32 ` Markus Armbruster
@ 2021-06-10 13:29 ` Peng Liang
0 siblings, 0 replies; 8+ messages in thread
From: Peng Liang @ 2021-06-10 13:29 UTC (permalink / raw)
To: Markus Armbruster
Cc: Paolo Bonzini, Daniel P. Berrangé, Zhenzhong Duan, qemu-devel
On 6/10/2021 3:32 PM, Markus Armbruster wrote:
> Peng Liang <liangpeng10@huawei.com> writes:
>
>> On 6/9/2021 8:15 PM, Daniel P. Berrangé wrote:
>>> On Wed, Jun 09, 2021 at 02:09:47PM +0200, Markus Armbruster wrote:
>>>> Paolo Bonzini <pbonzini@redhat.com> writes:
>>>>
>>>>> On 10/06/21 10:47, Zhenzhong Duan wrote:
>>>>>> Based on the description of error_setg(), the local variable err in
>>>>>> qemu_maybe_daemonize() should be initialized to NULL.
>>>>>> Without fix, the uninitialized *errp triggers assert failure which
>>>>>> doesn't show much valuable information.
>>>>>> Before the fix:
>>>>>> qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' failed.
>>>>>> After fix:
>>>>>> qemu-system-x86_64: cannot create PID file: Cannot open pid file: Permission denied
>>>>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>>>>> ---
>>>>>> softmmu/vl.c | 2 +-
>>>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>> diff --git a/softmmu/vl.c b/softmmu/vl.c
>>>>>> index 326c1e9080..feb4d201f3 100644
>>>>>> --- a/softmmu/vl.c
>>>>>> +++ b/softmmu/vl.c
>>>>>> @@ -2522,7 +2522,7 @@ static void qemu_process_help_options(void)
>>>>>> static void qemu_maybe_daemonize(const char *pid_file)
>>>>>> {
>>>>>> - Error *err;
>>>>>> + Error *err = NULL;
>>>>
>>>> Common mistake, I'm afraid.
>>>
>>> Initializing isn't likely to be a performance impact, so I'd think
>>> we should make 'checkpatch.pl' complain about any 'Error *' variable
>>> that is not initialized to NULL, as a safety net, even if not technically
>>> required in some cases.
>>>
>>> Regards,
>>> Daniel
>>>
>>
>> Hi,
>> Could we add a coccinelle script to check (and fix) these problems? e.g.:
>
> Coccinelle is good for finding and fixing instances of bad patterns that
> have crept in. checkpatch is good for keeping them out. Both has its
> uses.
>
>> @ r @
>> identifier id;
>> @@
>> Error *id
>> + = NULL
>> ;
>>
>> Using this script, I found that local variable err in
>> qemu_init_subsystems is not initialized to NULL too.
>
> Crash bug, broken in commit efd7ab22fb "vl: extract
> qemu_init_subsystems", v6.0.0. Care to submit a fix?
Have sent :)
>
>> The script is not
>> prefect though, it will initialize all global/static 'Error *' variables
>> and all local 'Error *' variables in util/error.c to NULL, which is
>> unnecessary.
>
> Excluding util/error.c is easy once you know how to:
>
> @ depends on !(file in "util/error.c")@
> identifier id;
> @@
> ...
>
> Excluding variable definitions with static storage duraction shouldn't
> be too hard, either. If Coccinelle is sufficiently clever, adding
> keyword auto suffices. Else, try matching keyword static separately,
> like so:
>
> (
> static Error *id;
> |
> - Error *id;
> + Error *id = NULL;
> )
>
> Completely untested.
>
Thanks for your improvement!
Thanks,
Peng
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-06-10 13:32 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-10 8:47 [PATCH] vl: Fix an assert failure in error path Zhenzhong Duan
2021-06-09 9:30 ` Paolo Bonzini
2021-06-09 12:09 ` Markus Armbruster
2021-06-09 12:15 ` Daniel P. Berrangé
2021-06-10 1:47 ` Peng Liang
2021-06-10 7:32 ` Markus Armbruster
2021-06-10 13:29 ` Peng Liang
2021-06-10 12:55 ` Paolo Bonzini
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