c7775b365e
To reproduce run the following on a terminal:
<snip>
cpu% leak -s `{pstree | grep termrc | sed 1q | awk '{print $1}'}
src(0x00209a82); // 12
src(0x0020b2a6); // 1
cpu% acid `{pstree | grep termrc | sed 1q | awk '{print $1}'}
/proc/358/text:amd64 plan 9 executable
/sys/lib/acid/port
/sys/lib/acid/amd64
acid: src(0x0020b2a6)
/sys/src/cmd/rc/plan9.c:169
164 if(runq->argv->words == 0)
165 poplist();
166 else {
167 free(runq->cmdfile);
168 int f = open(runq->argv->words->word, 0);
>169 runq->cmdfile = strdup(runq->argv->words->word);
170 runq->lexline = 1;
171 runq->pc--;
172 popword();
173 if(f>=0) execcmds(openfd(f));
174 }
acid:
</snap>
Another `runq->cmdfile` leak is present here (captured on a cpu server):
<snip>
277 ├listen [tcp * /rc/bin/service <nil>]
321 │├listen [/net/tcp/2 tcp!*!80]
322 │├listen [/net/tcp/3 tcp!*!17019]
324 ││└rc [/net/tcp/5 tcp!185.64.155.70!3516]
334 ││ ├rc -li
382 ││ │└pstree
336 ││ └rc
338 ││ └cat
323 │└listen [/net/tcp/4 tcp!*!17020]
278 ├listen [tcp * /rc/bin/service.auth <nil>]
320 │└listen [/net/tcp/1 tcp!*!567]
381 └closeproc
cpu% leak -s 336
src(0x00209a82); // 2
src(0x002051d2); // 1
cpu% acid 336
/proc/336/text:amd64 plan 9 executable
/sys/lib/acid/port
/sys/lib/acid/amd64
acid: src(0x002051d2)
/sys/src/cmd/rc/exec.c:1056
1051
1052 void
1053 Xsrcfile(void)
1054 {
1055 free(runq->cmdfile);
>1056 runq->cmdfile = strdup(runq->code[runq->pc++].s);
1057 }
acid:
</snap>
These leaks happen because we do not free cmdfile on all execution paths
where `Xreturn()` is invoked. In `/sys/src/cmd/rc/exec.c:/^Xreturn`
<snip>
void
Xreturn(void)
{
struct thread *p = runq;
turfredir();
while(p->argv) poplist();
codefree(p->code);
runq = p->ret;
free(p);
if(runq==0)
Exit(getstatus());
}
</snip>
Note how the function `Xreturn()` frees a heap allocated instance of type
`thread` with its members *except* the `cmdfile` member.
On some code paths where `Xreturn()` is called there is an attempt to free
`cmdfile`, however, there are some code paths where `Xreturn()` is called
where `cmdfile` is not freed, leading to a leak.
The attached patch calls `free(p->cmdfile)` in `Xreturn()` to avoid leaking
memory and handling the free in one place.
After applying the patch this particular leak is removed. There are still
other leaks in rc:
<snip>
277 ├listen [tcp * /rc/bin/service <nil>]
321 │├listen [/net/tcp/2 tcp!*!80]
322 │├listen [/net/tcp/3 tcp!*!17019]
324 ││└rc [/net/tcp/5 tcp!185.64.155.70!3516]
334 ││ ├rc -li
382 ││ │└pstree
336 ││ └rc
338 ││ └cat
323 │└listen [/net/tcp/4 tcp!*!17020]
278 ├listen [tcp * /rc/bin/service.auth <nil>]
320 │└listen [/net/tcp/1 tcp!*!567]
381 └closeproc
cpu% leak -s 336
src(0x00209a82); // 2
src(0x002051d2); // 1
cpu% acid 336
/proc/336/text:amd64 plan 9 executable
/sys/lib/acid/port
/sys/lib/acid/amd64
acid: src(0x00209a82)
/sys/src/cmd/rc/subr.c:9
4 #include "fns.h"
5
6 void *
7 emalloc(long n)
8 {
>9 void *p = malloc(n);
10 if(p==0)
11 panic("Can't malloc %d bytes", n);
12 return p;
13 }
14
</snap>
To help fixing those leaks emalloc(…) and erealloc(…) have been amended to use
setmalloctag(…) and setrealloctag(…). The actual fixes for other reported leaks
are *not* part of this merge and will follow.
|
||
|---|---|---|
| 386 | ||
| 68000 | ||
| 68020 | ||
| acme | ||
| adm/timezone | ||
| amd64 | ||
| arm | ||
| arm64 | ||
| lib | ||
| mips | ||
| power | ||
| power64 | ||
| rc | ||
| sparc | ||
| sparc64 | ||
| spim | ||
| sys | ||