Re: [Valgrind-users] memory leak problem

[John R. <jr...@bi...>]

The pattern
> 6cf7a000       4 ----- 0000000000000000 000:00000   [ anon ]
> 6cf7b000    8192 rw--- 0000000000000000 000:00000   [ anon ]
with one 4KiB page of no access (-----) adjacent to 8MiB of rw---
is [or perhaps, was] the default-sized stack of a thread.  When a
thread terminates, then glibc keeps that stack on a separate internal
list, and allocates the stack for a new thread from this list
if possible; else glibc uses mmap() to create a new stack.
It seems that there is no way to tell glibc to do it differently.
(You can change the default size by using pthread_attr_setstacksize(),
but you cannot change the policy of keeping old stacks for use by
new threads.)

The pattern
> 71000000     132 rw--- 0000000000000000 000:00000   [ anon ]
> 71021000     892 ----- 0000000000000000 000:00000   [ anon ]
with 132KiB of rw--- followed by 892KiB of no access is a
peculiar one that I do not recall seeing before.

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