[uclibc-ng-devel] TLS memory-leak with dlopen

If a shared library (so) is loaded using dlopen and utilizes thread-local storage (TLS), the memory will not be freed upon thread exit, resulting in a memory leak. This issue has been resolved in glibc-2.14. However, it remains unresolved in uClibc. The following patch is based on the patch made in glibc and has been validated as effective on the x86-64 architecture. diff --git a/libpthread/nptl/allocatestack.c b/libpthread/nptl/allocatestack.c index 7ef884543..941ef22f0 100644 --- a/libpthread/nptl/allocatestack.c +++ b/libpthread/nptl/allocatestack.c @@ -24,6 +24,7 @@ #include <unistd.h> #include <sys/mman.h> #include <sys/param.h> +#include <dl-tls.h> #include <tls.h> #include <lowlevellock.h> #include <link.h> @@ -241,6 +242,10 @@ get_cached_stack (size_t *sizep, void **memp) /* Clear the DTV. */ dtv_t *dtv = GET_DTV (TLS_TPADJ (result)); + for (size_t cnt = 0; cnt < dtv[-1].counter; ++cnt) + if (! dtv[1 + cnt].pointer.is_static + && dtv[1 + cnt].pointer.val != TLS_DTV_UNALLOCATED) + free (dtv[1 + cnt].pointer.val); memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t)); /* Re-initialize the TLS. */ diff --git a/libpthread/nptl/sysdeps/generic/dl-tls.c b/libpthread/nptl/sysdeps/generic/dl-tls.c index 7d25e4706..7b7991be8 100644 --- a/libpthread/nptl/sysdeps/generic/dl-tls.c +++ b/libpthread/nptl/sysdeps/generic/dl-tls.c @@ -45,8 +45,6 @@ to allow dynamic loading of modules defining IE-model TLS data. */ # define TLS_STATIC_SURPLUS 64 + DL_NNS * 100 -/* Value used for dtv entries for which the allocation is delayed. */ -# define TLS_DTV_UNALLOCATED ((void *) -1l) #ifndef SHARED extern dtv_t static_dtv; diff --git a/libpthread/nptl/sysdeps/x86_64/dl-tls.h b/libpthread/nptl/sysdeps/x86_64/dl-tls.h index d6c338cda..5cac55f33 100644 --- a/libpthread/nptl/sysdeps/x86_64/dl-tls.h +++ b/libpthread/nptl/sysdeps/x86_64/dl-tls.h @@ -26,3 +26,6 @@ typedef struct extern void *__tls_get_addr (tls_index *ti); + +/* Value used for dtv entries for which the allocation is delayed. */ +#define TLS_DTV_UNALLOCATED ((void *) -1l) Ref: https://sourceware.org/bugzilla/show_bug.cgi?id=12650 How to reproduce: ------------------------------------------------------------------------------------------------------------------------------------- 本邮件及其附件含有新华三集团的保密信息，仅限于发送给上面地址中列出 的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制、 或散发）本邮件中的信息。如果您错收了本邮件，请您立即电话或邮件通知发件人并删除本 邮件！ This e-mail and its attachments contain confidential information from New H3C, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it!