* [PATCH] perf mem2node: avoid double free related to realloc
@ 2020-03-14 4:28 Ian Rogers
2020-03-14 14:23 ` Jiri Olsa
0 siblings, 1 reply; 5+ messages in thread
From: Ian Rogers @ 2020-03-14 4:28 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
linux-kernel, clang-built-linux
Cc: Stephane Eranian, Ian Rogers
Realloc of size zero is a free not an error, avoid this causing a double
free. Caught by clang's address sanitizer:
==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in thread T0:
#0 0x5649659297fd in free llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3
#1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2
#2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2
#3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2
#4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
#5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
#6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
#7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
#8 0x564965942e41 in main tools/perf/perf.c:538:3
0x6020000015f0 is located 0 bytes inside of 1-byte region [0x6020000015f0,0x6020000015f1)
freed by thread T0 here:
#0 0x564965929da3 in realloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16
#2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
#3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
#4 0x564965944348 in run_builtin tools/perf/perf.c:312:11
#5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
#6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
#7 0x564965942e41 in main tools/perf/perf.c:538:3
previously allocated by thread T0 here:
#0 0x564965929c42 in calloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
#1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9
#2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12
#3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
#4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
#5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
#6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
#7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
#8 0x564965942e41 in main tools/perf/perf.c:538:3
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/mem2node.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/mem2node.c b/tools/perf/util/mem2node.c
index 797d86a1ab09..7f97aa69eb65 100644
--- a/tools/perf/util/mem2node.c
+++ b/tools/perf/util/mem2node.c
@@ -95,7 +95,7 @@ int mem2node__init(struct mem2node *map, struct perf_env *env)
/* Cut unused entries, due to merging. */
tmp_entries = realloc(entries, sizeof(*entries) * j);
- if (tmp_entries)
+ if (j == 0 || tmp_entries)
entries = tmp_entries;
for (i = 0; i < j; i++) {
--
2.25.1.481.gfbce0eb801-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] perf mem2node: avoid double free related to realloc
2020-03-14 4:28 [PATCH] perf mem2node: avoid double free related to realloc Ian Rogers
@ 2020-03-14 14:23 ` Jiri Olsa
2020-03-14 16:49 ` Ian Rogers
0 siblings, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2020-03-14 14:23 UTC (permalink / raw)
To: Ian Rogers
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Namhyung Kim, linux-kernel,
clang-built-linux, Stephane Eranian
On Fri, Mar 13, 2020 at 09:28:26PM -0700, Ian Rogers wrote:
> Realloc of size zero is a free not an error, avoid this causing a double
> free. Caught by clang's address sanitizer:
>
> ==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in thread T0:
> #0 0x5649659297fd in free llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3
> #1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2
> #2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2
> #3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2
> #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> #8 0x564965942e41 in main tools/perf/perf.c:538:3
>
> 0x6020000015f0 is located 0 bytes inside of 1-byte region [0x6020000015f0,0x6020000015f1)
> freed by thread T0 here:
> #0 0x564965929da3 in realloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
> #1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16
> #2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
> #3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> #4 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> #5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> #6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> #7 0x564965942e41 in main tools/perf/perf.c:538:3
>
> previously allocated by thread T0 here:
> #0 0x564965929c42 in calloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
> #1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9
> #2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12
> #3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
> #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> #8 0x564965942e41 in main tools/perf/perf.c:538:3
>
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/util/mem2node.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/mem2node.c b/tools/perf/util/mem2node.c
> index 797d86a1ab09..7f97aa69eb65 100644
> --- a/tools/perf/util/mem2node.c
> +++ b/tools/perf/util/mem2node.c
> @@ -95,7 +95,7 @@ int mem2node__init(struct mem2node *map, struct perf_env *env)
>
> /* Cut unused entries, due to merging. */
> tmp_entries = realloc(entries, sizeof(*entries) * j);
> - if (tmp_entries)
> + if (j == 0 || tmp_entries)
nice catch.. I wonder if we should fail in here, or at least
warn that there're no entris.. which is really strange ;-)
thanks,
jirka
> entries = tmp_entries;
>
> for (i = 0; i < j; i++) {
> --
> 2.25.1.481.gfbce0eb801-goog
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] perf mem2node: avoid double free related to realloc
2020-03-14 14:23 ` Jiri Olsa
@ 2020-03-14 16:49 ` Ian Rogers
2020-03-15 9:30 ` Jiri Olsa
0 siblings, 1 reply; 5+ messages in thread
From: Ian Rogers @ 2020-03-14 16:49 UTC (permalink / raw)
To: Jiri Olsa
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Namhyung Kim, LKML,
clang-built-linux, Stephane Eranian
On Sat, Mar 14, 2020 at 7:23 AM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Fri, Mar 13, 2020 at 09:28:26PM -0700, Ian Rogers wrote:
> > Realloc of size zero is a free not an error, avoid this causing a double
> > free. Caught by clang's address sanitizer:
> >
> > ==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in thread T0:
> > #0 0x5649659297fd in free llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3
> > #1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2
> > #2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2
> > #3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2
> > #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > #8 0x564965942e41 in main tools/perf/perf.c:538:3
> >
> > 0x6020000015f0 is located 0 bytes inside of 1-byte region [0x6020000015f0,0x6020000015f1)
> > freed by thread T0 here:
> > #0 0x564965929da3 in realloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
> > #1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16
> > #2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
> > #3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > #4 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > #5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > #6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > #7 0x564965942e41 in main tools/perf/perf.c:538:3
> >
> > previously allocated by thread T0 here:
> > #0 0x564965929c42 in calloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
> > #1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9
> > #2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12
> > #3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
> > #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > #8 0x564965942e41 in main tools/perf/perf.c:538:3
> >
> > Signed-off-by: Ian Rogers <irogers@google.com>
> > ---
> > tools/perf/util/mem2node.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/mem2node.c b/tools/perf/util/mem2node.c
> > index 797d86a1ab09..7f97aa69eb65 100644
> > --- a/tools/perf/util/mem2node.c
> > +++ b/tools/perf/util/mem2node.c
> > @@ -95,7 +95,7 @@ int mem2node__init(struct mem2node *map, struct perf_env *env)
> >
> > /* Cut unused entries, due to merging. */
> > tmp_entries = realloc(entries, sizeof(*entries) * j);
> > - if (tmp_entries)
> > + if (j == 0 || tmp_entries)
>
> nice catch.. I wonder if we should fail in here, or at least
> warn that there're no entris.. which is really strange ;-)
The workload was the stream benchmark with perf c2c, but stream isn't
particularly long running. Not sure how j became 0, there's 2
possibilities in the code. The worry with a warning is the spam, so I
just wanted to make the code correct.
Thanks,
Ian
> thanks,
> jirka
>
> > entries = tmp_entries;
> >
> > for (i = 0; i < j; i++) {
> > --
> > 2.25.1.481.gfbce0eb801-goog
> >
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] perf mem2node: avoid double free related to realloc
2020-03-14 16:49 ` Ian Rogers
@ 2020-03-15 9:30 ` Jiri Olsa
2020-03-20 18:25 ` Ian Rogers
0 siblings, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2020-03-15 9:30 UTC (permalink / raw)
To: Ian Rogers
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Namhyung Kim, LKML,
clang-built-linux, Stephane Eranian
On Sat, Mar 14, 2020 at 09:49:37AM -0700, Ian Rogers wrote:
> On Sat, Mar 14, 2020 at 7:23 AM Jiri Olsa <jolsa@redhat.com> wrote:
> >
> > On Fri, Mar 13, 2020 at 09:28:26PM -0700, Ian Rogers wrote:
> > > Realloc of size zero is a free not an error, avoid this causing a double
> > > free. Caught by clang's address sanitizer:
> > >
> > > ==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in thread T0:
> > > #0 0x5649659297fd in free llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3
> > > #1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2
> > > #2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2
> > > #3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2
> > > #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > > #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > > #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > > #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > > #8 0x564965942e41 in main tools/perf/perf.c:538:3
> > >
> > > 0x6020000015f0 is located 0 bytes inside of 1-byte region [0x6020000015f0,0x6020000015f1)
> > > freed by thread T0 here:
> > > #0 0x564965929da3 in realloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
> > > #1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16
> > > #2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
> > > #3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > > #4 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > > #5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > > #6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > > #7 0x564965942e41 in main tools/perf/perf.c:538:3
> > >
> > > previously allocated by thread T0 here:
> > > #0 0x564965929c42 in calloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
> > > #1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9
> > > #2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12
> > > #3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
> > > #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > > #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > > #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > > #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > > #8 0x564965942e41 in main tools/perf/perf.c:538:3
> > >
> > > Signed-off-by: Ian Rogers <irogers@google.com>
> > > ---
> > > tools/perf/util/mem2node.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/tools/perf/util/mem2node.c b/tools/perf/util/mem2node.c
> > > index 797d86a1ab09..7f97aa69eb65 100644
> > > --- a/tools/perf/util/mem2node.c
> > > +++ b/tools/perf/util/mem2node.c
> > > @@ -95,7 +95,7 @@ int mem2node__init(struct mem2node *map, struct perf_env *env)
> > >
> > > /* Cut unused entries, due to merging. */
> > > tmp_entries = realloc(entries, sizeof(*entries) * j);
> > > - if (tmp_entries)
> > > + if (j == 0 || tmp_entries)
> >
> > nice catch.. I wonder if we should fail in here, or at least
> > warn that there're no entris.. which is really strange ;-)
>
> The workload was the stream benchmark with perf c2c, but stream isn't
> particularly long running. Not sure how j became 0, there's 2
> possibilities in the code. The worry with a warning is the spam, so I
> just wanted to make the code correct.
I was wondering if we should fail completely,
but we might break some c2c expected behaviour
how about just WARN_ONCE pn j == 0, and then
the lookup will fail already with:
if (WARN_ONCE(node < 0, "WARNING: failed to find node\n"))
return;
just get enough hints ;-)
jirka
>
> Thanks,
> Ian
>
> > thanks,
> > jirka
> >
> > > entries = tmp_entries;
> > >
> > > for (i = 0; i < j; i++) {
> > > --
> > > 2.25.1.481.gfbce0eb801-goog
> > >
> >
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] perf mem2node: avoid double free related to realloc
2020-03-15 9:30 ` Jiri Olsa
@ 2020-03-20 18:25 ` Ian Rogers
0 siblings, 0 replies; 5+ messages in thread
From: Ian Rogers @ 2020-03-20 18:25 UTC (permalink / raw)
To: Jiri Olsa
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Namhyung Kim, LKML,
clang-built-linux, Stephane Eranian
On Sun, Mar 15, 2020 at 2:30 AM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Sat, Mar 14, 2020 at 09:49:37AM -0700, Ian Rogers wrote:
> > On Sat, Mar 14, 2020 at 7:23 AM Jiri Olsa <jolsa@redhat.com> wrote:
> > >
> > > On Fri, Mar 13, 2020 at 09:28:26PM -0700, Ian Rogers wrote:
> > > > Realloc of size zero is a free not an error, avoid this causing a double
> > > > free. Caught by clang's address sanitizer:
> > > >
> > > > ==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in thread T0:
> > > > #0 0x5649659297fd in free llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3
> > > > #1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2
> > > > #2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2
> > > > #3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2
> > > > #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > > > #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > > > #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > > > #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > > > #8 0x564965942e41 in main tools/perf/perf.c:538:3
> > > >
> > > > 0x6020000015f0 is located 0 bytes inside of 1-byte region [0x6020000015f0,0x6020000015f1)
> > > > freed by thread T0 here:
> > > > #0 0x564965929da3 in realloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
> > > > #1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16
> > > > #2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
> > > > #3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > > > #4 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > > > #5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > > > #6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > > > #7 0x564965942e41 in main tools/perf/perf.c:538:3
> > > >
> > > > previously allocated by thread T0 here:
> > > > #0 0x564965929c42 in calloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
> > > > #1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9
> > > > #2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12
> > > > #3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
> > > > #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
> > > > #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
> > > > #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
> > > > #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
> > > > #8 0x564965942e41 in main tools/perf/perf.c:538:3
> > > >
> > > > Signed-off-by: Ian Rogers <irogers@google.com>
> > > > ---
> > > > tools/perf/util/mem2node.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/tools/perf/util/mem2node.c b/tools/perf/util/mem2node.c
> > > > index 797d86a1ab09..7f97aa69eb65 100644
> > > > --- a/tools/perf/util/mem2node.c
> > > > +++ b/tools/perf/util/mem2node.c
> > > > @@ -95,7 +95,7 @@ int mem2node__init(struct mem2node *map, struct perf_env *env)
> > > >
> > > > /* Cut unused entries, due to merging. */
> > > > tmp_entries = realloc(entries, sizeof(*entries) * j);
> > > > - if (tmp_entries)
> > > > + if (j == 0 || tmp_entries)
> > >
> > > nice catch.. I wonder if we should fail in here, or at least
> > > warn that there're no entris.. which is really strange ;-)
> >
> > The workload was the stream benchmark with perf c2c, but stream isn't
> > particularly long running. Not sure how j became 0, there's 2
> > possibilities in the code. The worry with a warning is the spam, so I
> > just wanted to make the code correct.
>
> I was wondering if we should fail completely,
> but we might break some c2c expected behaviour
>
> how about just WARN_ONCE pn j == 0, and then
> the lookup will fail already with:
>
> if (WARN_ONCE(node < 0, "WARNING: failed to find node\n"))
> return;
>
> just get enough hints ;-)
Sorry for the delay. I sent a v2 hopefully doing what you asked :-)
https://lkml.org/lkml/2020/3/20/858
Thanks,
Ian
> jirka
>
> >
> > Thanks,
> > Ian
> >
> > > thanks,
> > > jirka
> > >
> > > > entries = tmp_entries;
> > > >
> > > > for (i = 0; i < j; i++) {
> > > > --
> > > > 2.25.1.481.gfbce0eb801-goog
> > > >
> > >
> >
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-03-20 18:26 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-14 4:28 [PATCH] perf mem2node: avoid double free related to realloc Ian Rogers
2020-03-14 14:23 ` Jiri Olsa
2020-03-14 16:49 ` Ian Rogers
2020-03-15 9:30 ` Jiri Olsa
2020-03-20 18:25 ` Ian Rogers
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