When debugging a program on ARMv7 with thread-local storage declared using "__thread", attempting to print a thread-local variable will result in the following message: Cannot find thread-local storage for Thread <snip> (LWP <snip>), executable file /tmp/tls: capability not available This can be traced back to uclibc libpthread/nptl_db/td_thr_tls_get_addr.c which gdb uses to look up the address of the TLS. The function returns TD_NOCAPAB due to a mismatch in size between the DTV pointer and the size recorded in the db description. The problem lies in libpthread/nptl_db/db_info.c which initializes the db with the sizeof the union dtv. Instead it should be the sizeof a pointer to union dtv. Fixed the initial size for dtvp to sizeof a pointer, instead of sizeof the union. Refer to: http://sourceware.org/ml/libc-alpha/2006-10/msg00088.html https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=416b630981788c1f08e7… Signed-off-by: Junling Zheng &lt;zhengjunling(a)huawei.com&gt; --- libpthread/nptl_db/db_info.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libpthread/nptl_db/db_info.c b/libpthread/nptl_db/db_info.c index a57a053..159a027 100644 --- a/libpthread/nptl_db/db_info.c +++ b/libpthread/nptl_db/db_info.c @@ -60,7 +60,7 @@ extern bool __nptl_initial_report_events; i.e. at the very end of the area covered by TLS_PRE_TCB_SIZE. */ DESC (_thread_db_pthread_dtvp, TLS_PRE_TCB_SIZE + offsetof (tcbhead_t, dtv) - - (TLS_TCB_SIZE == 0 ? sizeof (tcbhead_t) : 0), union dtv) + - (TLS_TCB_SIZE == 0 ? sizeof (tcbhead_t) : 0), union dtv *) #endif