path: root/arch/um/sys-x86_64
diff options
authorPaolo 'Blaisorblade' Giarrusso <>2005-07-14 00:33:36 -0700
committerLinus Torvalds <>2005-07-14 09:00:24 -0700
commit1feb8d2d7396748fb3bd6795d09bbfbdd4c03dff (patch)
tree73d7dbb979a107859fb40730555cb10ca6b4cbbb /arch/um/sys-x86_64
parentbcb01b8a67476e6f748086e626df8424cc27036d (diff)
[PATCH] uml: workaround host bug in "TT mode vs. NPTL link fix"
A big bug has been diagnosed on hosts running the SKAS patch and built with CONFIG_REGPARM, due to some missing prevent_tail_call(). On these hosts, this workaround is needed to avoid triggering that bug, because "to" is kept by GCC only in EBX, which is corrupted at the return of mmap2(). Since to trigger this bug int 0x80 must be used when doing the call, it rarely manifests itself, so I'd prefer to get this merged to workaround that host bug, since it should cause no functional change. Still, you might prefer to drop it, I'll leave this to you. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <> Cc: Jeff Dike <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'arch/um/sys-x86_64')
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/um/sys-x86_64/unmap.c b/arch/um/sys-x86_64/unmap.c
index bc7094cce47e..f4a4bffd8a18 100644
--- a/arch/um/sys-x86_64/unmap.c
+++ b/arch/um/sys-x86_64/unmap.c
@@ -15,7 +15,7 @@ int switcheroo(int fd, int prot, void *from, void *to, int size)
if(munmap(to, size) < 0){
- if(mmap(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) != to){
+ if(mmap(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) == (void*) -1){
if(munmap(from, size) < 0){