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authorFlorian Weimer <fweimer@redhat.com>2021-05-10 10:31:41 +0200
committerFlorian Weimer <fweimer@redhat.com>2021-05-10 10:31:41 +0200
commit1c75f89613a0b2428c21c19598559a2d64221cde (patch)
tree55eb68a014e7e9a4bde5f9e095f03fa4bbb019a6 /sysdeps
parent321789f61aa93c14390535aa3cf01846633cd022 (diff)
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Linux: Explicitly disable cancellation checking in the dynamic loader
Historically, SINGLE_THREAD_P is defined to 1 in the dynamic loader.
This has the side effect of disabling cancellation points.  In order
to enable future use of SINGLE_THREAD_P for single-thread
optimizations in the dynamic loader (which becomes important once
more code is moved from libpthread), introduce a new
NO_SYSCALL_CANCEL_CHECKING macro which is always 1 for IS_IN (rtld),
indepdently of the actual SINGLE_THREAD_P value.

Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/unix/sysdep.h11
1 files changed, 9 insertions, 2 deletions
diff --git a/sysdeps/unix/sysdep.h b/sysdeps/unix/sysdep.h
index 2fa6bfa135..664d093c05 100644
--- a/sysdeps/unix/sysdep.h
+++ b/sysdeps/unix/sysdep.h
@@ -88,10 +88,17 @@
 #define INLINE_SYSCALL_CALL(...) \
   __INLINE_SYSCALL_DISP (__INLINE_SYSCALL, __VA_ARGS__)
 
+#if IS_IN (rtld)
+/* All cancellation points are compiled out in the dynamic loader.  */
+# define NO_SYSCALL_CANCEL_CHECKING 1
+#else
+# define NO_SYSCALL_CANCEL_CHECKING SINGLE_THREAD_P
+#endif
+
 #define SYSCALL_CANCEL(...) \
   ({									     \
     long int sc_ret;							     \
-    if (SINGLE_THREAD_P) 						     \
+    if (NO_SYSCALL_CANCEL_CHECKING)					     \
       sc_ret = INLINE_SYSCALL_CALL (__VA_ARGS__); 			     \
     else								     \
       {									     \
@@ -107,7 +114,7 @@
 #define INTERNAL_SYSCALL_CANCEL(...) \
   ({									     \
     long int sc_ret;							     \
-    if (SINGLE_THREAD_P) 						     \
+    if (NO_SYSCALL_CANCEL_CHECKING) 					     \
       sc_ret = INTERNAL_SYSCALL_CALL (__VA_ARGS__); 			     \
     else								     \
       {									     \