* [PATCH] Fix assert after goto failure
@ 2021-03-01 12:44 Tom de Vries
2021-03-02 13:14 ` Mark Wielaard
0 siblings, 1 reply; 2+ messages in thread
From: Tom de Vries @ 2021-03-01 12:44 UTC (permalink / raw)
To: dwz, jakub, mark
Hi,
Consider the following code in function dwz:
...
else if (write_aranges (dso))
{
cleanup ();
failure:
ret = 1;
}
...
char *p1 = realpath (file, NULL);
char *p2 = realpath (multifile, NULL);
...
if (p1 == NULL || p2 == NULL)
{
...
error (0, 0, "Could not compute relative multifile "
"pathname from %s to %s",
file, multifile);
goto failure;
...
I've managed to triggered this error in the following way.
First we do this setup:
...
$ mkdir tmpdir
$ ln -s tmpdir tmpdir-slink
$ cp hello 1
$ cp 1 2
...
Then we want to run dwz with a common file in tmpdir using the symlink tmpdir-slink:
...
$ dwz -m ./tmpdir-slink/3 -r 1 2
...
but, stop just before calling realpath and remove the symlink to make the p2
realpath call return NULL.
We can do that using gdb:
...
$ gdb -batch \
-ex "b 15451" \
-ex run \
-ex "shell rm -f tmpdir-slink" \
-ex cont \
--args ./dwz -m ./tmpdir-slink/3 -r 1 2
Breakpoint 1 at 0x382d1: file dwz.c, line 15451.
Breakpoint 1, dwz (file=0x7fffffffe285 "1", outfile=0x0, res=0x5555557a5260,
resa=0x0, files=0x7fffffffdeb8) at dwz.c:15451
15451 if (!multifile_relative)
dwz: Could not compute relative multifile pathname from 1 to ./tmpdir-slink/3
dwz: dwz.c:2170: off_htab_add_die: Assertion `*slot == NULL' failed.
Program received signal SIGABRT, Aborted.
0x00007ffff75fffb7 in raise () from /lib/x86_64-linux-gnu/libc.so.6
...
but we hit an assertion.
This is because cleanup is not called.
Fix this by moving the failure label up one line.
Any comments?
Thanks,
- Tom
Fix assert after goto failure
2021-03-01 Tom de Vries <tdevries@suse.de>
* dwz.c (dwz): Move failure label to before cleanup.
---
dwz.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/dwz.c b/dwz.c
index 8eb4f1d..d5fe7b1 100644
--- a/dwz.c
+++ b/dwz.c
@@ -15434,8 +15434,8 @@ dwz (const char *file, const char *outfile, struct file_result *res,
}
else if (write_aranges (dso))
{
- cleanup ();
failure:
+ cleanup ();
ret = 1;
}
else
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] Fix assert after goto failure
2021-03-01 12:44 [PATCH] Fix assert after goto failure Tom de Vries
@ 2021-03-02 13:14 ` Mark Wielaard
0 siblings, 0 replies; 2+ messages in thread
From: Mark Wielaard @ 2021-03-02 13:14 UTC (permalink / raw)
To: Tom de Vries, dwz, jakub
Hi Tom,
On Mon, 2021-03-01 at 13:44 +0100, Tom de Vries wrote:
> This is because cleanup is not called.
>
> Fix this by moving the failure label up one line.
>
> Any comments?
This looks consistent with how the rest of the code paths calls cleanup
before returning an error.
Thanks,
Mark
> Fix assert after goto failure
>
> 2021-03-01 Tom de Vries <tdevries@suse.de>
>
> * dwz.c (dwz): Move failure label to before cleanup.
>
> ---
> dwz.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/dwz.c b/dwz.c
> index 8eb4f1d..d5fe7b1 100644
> --- a/dwz.c
> +++ b/dwz.c
> @@ -15434,8 +15434,8 @@ dwz (const char *file, const char *outfile,
> struct file_result *res,
> }
> else if (write_aranges (dso))
> {
> - cleanup ();
> failure:
> + cleanup ();
> ret = 1;
> }
> else
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-03-02 13:14 ` Mark Wielaard
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