The patch titled
uml: host VDSO fix
has been removed from the -mm tree. Its filename was
uml-host-vdso-fix.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: uml: host VDSO fix
From: Jeff Dike <jdike@xxxxxxxxxxx>
This fixes a problem seen by a number of people running UML on newer host
kernels. init would hang with an infinite segfault loop.
It turns out that the host kernel was providing a AT_SYSINFO_EHDR of
0xffffe000, which faked UML into believing that the host VDSO page could be
reused. However, AT_SYSINFO pointed into the middle of the address space, and
was unmapped as a result. Because UML was providing AT_SYSINFO_EHDR and
AT_SYSINFO to its own processes, these would branch to nowhere when trying to
use the VDSO.
The fix is to also check the location of AT_SYSINFO when deciding whether to
use the host's VDSO.
Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/um/os-Linux/elf_aux.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN arch/um/os-Linux/elf_aux.c~uml-host-vdso-fix arch/um/os-Linux/elf_aux.c
--- a/arch/um/os-Linux/elf_aux.c~uml-host-vdso-fix
+++ a/arch/um/os-Linux/elf_aux.c
@@ -39,6 +39,9 @@ __init void scan_elf_aux( char **envp)
switch ( auxv->a_type ) {
case AT_SYSINFO:
__kernel_vsyscall = auxv->a_un.a_val;
+ /* See if the page is under TASK_SIZE */
+ if (__kernel_vsyscall < (unsigned long) envp)
+ __kernel_vsyscall = 0;
break;
case AT_SYSINFO_EHDR:
vsyscall_ehdr = auxv->a_un.a_val;
_
Patches currently in -mm which might be from jdike@xxxxxxxxxxx are
origin.patch
remove-hardcoding-of-hard_smp_processor_id-on-up.patch
remove-hardcoding-of-hard_smp_processor_id-on-up-move-definition-of-hard_smp_processor_id-to-asm-smph.patch
uml-delete-unused-code.patch
uml-formatting-fixes.patch
uml-host_info-tidying.patch
uml-fix-prototypes.patch
-
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