From: "Olivier Delbeke" <Olivier.Delbeke@awtce.be>
To: lttng-dev@lists.lttng.org
Sent: Tuesday, January 13, 2015 10:50:38 AM
Subject: [lttng-dev] Addition of the return address to        liblttng-ust-libc-wrapper

Hi guys,

I am using liblttng-ust-libc-wrapper to detect memory leaks in my applications.
In order to identify not only the thread where the unfreed allocations are done, but also the calling function, I extended the liblttng-ust-libc-wrapper to log the "return address" (__builtin_return_address(0)) in addition to the parameters of malloc(). It solves my problem and does not affect Trace Compass.
Was this the right thing to do ?

If it is, then I guess that it might interest other people too.

diff -Nurd b/liblttng-ust-libc-wrapper/lttng-ust-malloc.c c/liblttng-ust-libc-wrapper/lttng-ust-malloc.c
--- b/liblttng-ust-libc-wrapper/lttng-ust-malloc.c 2015-01-06 17:14:34.000000000 +0100
+++ c/liblttng-ust-libc-wrapper/lttng-ust-malloc.c 2015-01-06 17:16:40.811145106 +0100
@@ -260,7 +260,7 @@
  }
  retval = cur_alloc.malloc(size);
  if (URCU_TLS(malloc_nesting) == 1) {
- tracepoint(ust_libc, malloc, size, retval);
+ tracepoint(ust_libc, malloc, size, retval, __builtin_return_address(0) );
  }
  URCU_TLS(malloc_nesting)--;
  return retval;
@@ -279,7 +279,7 @@
  }
 
  if (URCU_TLS(malloc_nesting) == 1) {
- tracepoint(ust_libc, free, ptr);
+ tracepoint(ust_libc, free, ptr, __builtin_return_address(0) );
  }
 
  if (cur_alloc.free == NULL) {
@@ -308,7 +308,7 @@
  }
  retval = cur_alloc.calloc(nmemb, size);
  if (URCU_TLS(malloc_nesting) == 1) {
- tracepoint(ust_libc, calloc, nmemb, size, retval);
+ tracepoint(ust_libc, calloc, nmemb, size, retval, __builtin_return_address(0) );
  }
  URCU_TLS(malloc_nesting)--;
  return retval;
@@ -360,7 +360,7 @@
  retval = cur_alloc.realloc(ptr, size);
 end:
  if (URCU_TLS(malloc_nesting) == 1) {
- tracepoint(ust_libc, realloc, ptr, size, retval);
+ tracepoint(ust_libc, realloc, ptr, size, retval, __builtin_return_address(0) );
  }
  URCU_TLS(malloc_nesting)--;
  return retval;
@@ -380,7 +380,7 @@
  }
  retval = cur_alloc.memalign(alignment, size);
  if (URCU_TLS(malloc_nesting) == 1) {
- tracepoint(ust_libc, memalign, alignment, size, retval);
+ tracepoint(ust_libc, memalign, alignment, size, retval, __builtin_return_address(0) );
  }
  URCU_TLS(malloc_nesting)--;
  return retval;
@@ -401,7 +401,7 @@
  retval = cur_alloc.posix_memalign(memptr, alignment, size);
  if (URCU_TLS(malloc_nesting) == 1) {
  tracepoint(ust_libc, posix_memalign, *memptr, alignment, size,
- retval);
+ retval, __builtin_return_address(0) );
  }
  URCU_TLS(malloc_nesting)--;
  return retval;
diff -Nurd b/liblttng-ust-libc-wrapper/ust_libc.h c/liblttng-ust-libc-wrapper/ust_libc.h
--- b/liblttng-ust-libc-wrapper/ust_libc.h 2015-01-06 17:14:34.000000000 +0100
+++ c/liblttng-ust-libc-wrapper/ust_libc.h 2015-01-06 17:16:40.811145106 +0100
@@ -33,54 +33,60 @@
 #include <lttng/tracepoint.h>
 
 TRACEPOINT_EVENT(ust_libc, malloc,
- TP_ARGS(size_t, size, void *, ptr),
+ TP_ARGS(size_t, size, void *, ptr, void *, ra),
  TP_FIELDS(
  ctf_integer(size_t, size, size)
  ctf_integer_hex(void *, ptr, ptr)
+ ctf_integer_hex(void *, ra, ra)
  )
 )
 
 TRACEPOINT_EVENT(ust_libc, free,
- TP_ARGS(void *, ptr),
+ TP_ARGS(void *, ptr, void *, ra),
  TP_FIELDS(
  ctf_integer_hex(void *, ptr, ptr)
+ ctf_integer_hex(void *, ra, ra)
  )
 )
 
 TRACEPOINT_EVENT(ust_libc, calloc,
- TP_ARGS(size_t, nmemb, size_t, size, void *, ptr),
+ TP_ARGS(size_t, nmemb, size_t, size, void *, ptr, void *, ra),
  TP_FIELDS(
  ctf_integer(size_t, nmemb, nmemb)
  ctf_integer(size_t, size, size)
  ctf_integer_hex(void *, ptr, ptr)
+ ctf_integer_hex(void *, ra, ra)
  )
 )
 
 TRACEPOINT_EVENT(ust_libc, realloc,
- TP_ARGS(void *, in_ptr, size_t, size, void *, ptr),
+ TP_ARGS(void *, in_ptr, size_t, size, void *, ptr, void *, ra),
  TP_FIELDS(
  ctf_integer_hex(void *, in_ptr, in_ptr)
  ctf_integer(size_t, size, size)
  ctf_integer_hex(void *, ptr, ptr)
+ ctf_integer_hex(void *, ra, ra)
  )
 )
 
 TRACEPOINT_EVENT(ust_libc, memalign,
- TP_ARGS(size_t, alignment, size_t, size, void *, ptr),
+ TP_ARGS(size_t, alignment, size_t, size, void *, ptr, void *, ra),
  TP_FIELDS(
  ctf_integer(size_t, alignment, alignment)
  ctf_integer(size_t, size, size)
  ctf_integer_hex(void *, ptr, ptr)
+ ctf_integer_hex(void *, ra, ra)
  )
 )
 
 TRACEPOINT_EVENT(ust_libc, posix_memalign,
- TP_ARGS(void *, out_ptr, size_t, alignment, size_t, size, int, result),
+ TP_ARGS(void *, out_ptr, size_t, alignment, size_t, size, int, result, void *, ra),
  TP_FIELDS(
  ctf_integer_hex(void *, out_ptr, out_ptr)
  ctf_integer(size_t, alignment, alignment)
  ctf_integer(size_t, size, size)
  ctf_integer(int, result, result)
+ ctf_integer_hex(void *, ra, ra)
  )
 )
 
Best regards,

	Olivier Delbeke Senior Software Engineer Olivier.Delbeke@awtce.be / T. +32 2 389 25 53  AWTC Europe S.A. - Avenue de l’Industrie, 19 - 1420 Braine-l’Alleud - Belgium - www.aweurope.eu - www.aisin-aw.co.jp VAT : BE 0474.474.114 - RPM Nivelles

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