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[uclibc-ng-devel,25/32] nptl: Clear TLS area for static binaries.

Message ID 20180704155605.1892-26-christophe.lyon@st.com
State Accepted
Headers show
Series FDPIC ABI for ARM | expand

Commit Message

Christophe Lyon July 4, 2018, 3:55 p.m. UTC 
busybox init checks it has pid 1, but getpid() returns another value
when building busybox statically. This is because the corresponding
area is not cleared when allocated (it is allocated with
MAP_UNINITIALIZED, whose behavior depends on the Linux kernel's
CONFIG_MMAP_ALLOW_UNINITIALIZED).

This patch fixes the problem by explicitly clearing the memory area.

	* libpthread/nptl/sysdeps/generic/libc-tls.c (__libc_tls_setup):
	Clear tlsblock.

Signed-off-by: Mickaël Guêné <mickael.guene@st.com>
Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
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Patch

diff --git a/libpthread/nptl/sysdeps/generic/libc-tls.c b/libpthread/nptl/sysdeps/generic/libc-tls.c
index 725f3df..5f89c91 100644
--- a/libpthread/nptl/sysdeps/generic/libc-tls.c
+++ b/libpthread/nptl/sysdeps/generic/libc-tls.c
@@ -162,6 +162,7 @@  __libc_setup_tls (size_t tcbsize, size_t tcbalign)
   tcb_offset = roundup (tcbsize, align ?: 1);
   tlsblock = sbrk (tcb_offset + memsz + max_align
 		     + TLS_PRE_TCB_SIZE + GL(dl_tls_static_size));
+  memset(tlsblock, '\0', tcb_offset + memsz + max_align + TLS_PRE_TCB_SIZE + GL(dl_tls_static_size));
   tlsblock += TLS_PRE_TCB_SIZE;
 # else
   /* In case a model with a different layout for the TCB and DTV