| Message ID | 20181127233328.5164-1-philippe.waroquiers@skynet.be |
|---|---|
| State | New |
| Headers | show |
On 11/27/2018 11:33 PM, Philippe Waroquiers wrote: > Valgrind reports the below leak. > Fix the leak by using xrealloc, even for the first allocation, > as buf is static. > > ==29158== 5,888 bytes in 23 blocks are definitely lost in loss record 3,028 of 3,149 > ==29158== at 0x4C2BE2D: malloc (vg_replace_malloc.c:299) > ==29158== by 0x41B557: xmalloc (common-utils.c:44) > ==29158== by 0x60B7D9: forward_search_command(char const*, int) (source.c:1563) > ==29158== by 0x40BA68: cmd_func(cmd_list_element*, char const*, int) (cli-decode.c:1888) > ==29158== by 0x665300: execute_command(char const*, int) (top.c:630) > ... > > gdb/ChangeLog > 2018-11-28 Philippe Waroquiers <philippe.waroquiers@skynet.be> > > * source.c (forward_search_command): Fix leak by using > xrealloc even for the first allocation in the loop, as buf > is static. At first sight it would seem like 'buf' was made static to avoid allocating a growing buffer for each command invocation. But then, if that were the case, then you'd want 'cursize' to be static as well. The patch is OK, but I think that replacing 'buf' and all that manual buffer growing with a non-static gdb::def_vector<char> defined outside the outer loop would be even better. Thanks, Pedro Alves
On Thu, 2018-11-29 at 15:42 +0000, Pedro Alves wrote: > On 11/27/2018 11:33 PM, Philippe Waroquiers wrote: > > Valgrind reports the below leak. > > Fix the leak by using xrealloc, even for the first allocation, > > as buf is static. > > > > ==29158== 5,888 bytes in 23 blocks are definitely lost in loss record 3,028 of 3,149 > > ==29158== at 0x4C2BE2D: malloc (vg_replace_malloc.c:299) > > ==29158== by 0x41B557: xmalloc (common-utils.c:44) > > ==29158== by 0x60B7D9: forward_search_command(char const*, int) (source.c:1563) > > ==29158== by 0x40BA68: cmd_func(cmd_list_element*, char const*, int) (cli-decode.c:1888) > > ==29158== by 0x665300: execute_command(char const*, int) (top.c:630) > > ... > > > > gdb/ChangeLog > > 2018-11-28 Philippe Waroquiers <philippe.waroquiers@skynet.be> > > > > * source.c (forward_search_command): Fix leak by using > > xrealloc even for the first allocation in the loop, as buf > > is static. > > At first sight it would seem like 'buf' was made static to avoid > allocating a growing buffer for each command invocation. > > But then, if that were the case, then you'd want 'cursize' to be > static as well. > > The patch is OK, but I think that replacing 'buf' and all that > manual buffer growing with a non-static gdb::def_vector<char> defined > outside the outer loop would be even better. Thanks for the review, I have pushed this version, but I have added in my todo list the better fix + add a test : I found no explicit functional test for this command + my limited time on GDB development is also shared with analysing the remaining several hundreds tests having a definite leak :). Philippe
diff --git a/gdb/source.c b/gdb/source.c index e295fbf49e..c75351e65f 100644 --- a/gdb/source.c +++ b/gdb/source.c @@ -1560,7 +1560,7 @@ forward_search_command (const char *regex, int from_tty) int cursize, newsize; cursize = 256; - buf = (char *) xmalloc (cursize); + buf = (char *) xrealloc (buf, cursize); p = buf; c = fgetc (stream.get ());