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| author | Jeff Dike <jdike@addtoit.com> | 2007-02-28 20:13:31 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-03-01 14:53:38 -0800 |
| commit | 14251809b1921b1216568700f1be2f91a1cbb5c7 (patch) | |
| tree | 7162d7623138be81cc733968bf69d0511011d21b /arch | |
| parent | cf2775f175128fc9fd7ffb88981e068d27bc85db (diff) | |
| download | linux-14251809b1921b1216568700f1be2f91a1cbb5c7.tar.gz linux-14251809b1921b1216568700f1be2f91a1cbb5c7.tar.bz2 linux-14251809b1921b1216568700f1be2f91a1cbb5c7.zip | |
[PATCH] uml: host VDSO fix
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@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/um/os-Linux/elf_aux.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/um/os-Linux/elf_aux.c b/arch/um/os-Linux/elf_aux.c index 3a8d7e3aae0a..608784d4ec57 100644 --- a/arch/um/os-Linux/elf_aux.c +++ b/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; |