Bug#425567: linux-2.6: [HPPA] LWS CAS debug code enabled (not thread safe)
tag 425567 + patch
thanks
Please find below the patch sent to the lkml. Note that even if it is
workarounded in the glibc, it is important to fix it, as in very rare
conditions, the kernel could end up in returning always -EDEADLOCK.
diff -u a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -501,7 +501,7 @@
shlw %r20, 4, %r20
add %r20, %r28, %r20
-# ifdef ENABLE_LWS_DEBUG
+# if ENABLE_LWS_DEBUG
/*
DEBUG, check for deadlock!
If the thread register values are the same
@@ -550,7 +550,7 @@
perspective
*/
cas_action:
-#if defined CONFIG_SMP && defined ENABLE_LWS_DEBUG
+#if defined CONFIG_SMP && ENABLE_LWS_DEBUG
/* DEBUG */
mfctl %cr27, %r1
stw %r1, 4(%sr2,%r20)
@@ -562,7 +562,7 @@
#ifdef CONFIG_SMP
/* Free lock */
stw %r20, 0(%sr2,%r20)
-# ifdef ENABLE_LWS_DEBUG
+# if ENABLE_LWS_DEBUG
/* Clear thread register indicator */
stw %r0, 4(%sr2,%r20)
# endif
@@ -576,7 +576,7 @@
#ifdef CONFIG_SMP
/* Free lock */
stw %r20, 0(%sr2,%r20)
-# ifdef ENABLE_LWS_DEBUG
+# if ENABLE_LWS_DEBUG
stw %r0, 4(%sr2,%r20)
# endif
#endif
--
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
`. `' aurel32@debian.org | aurelien@aurel32.net
`- people.debian.org/~aurel32 | www.aurel32.net
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