ARM: fix a cockup in 48be69a02 (ARM: move signal handlers into a vdso-like page)
Unfortunately, I never committed the fix to a nasty oops which can
occur as a result of that commit:
------------[ cut here ]------------
kernel BUG at /home/olof/work/batch/include/linux/mm.h:414!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 490 Comm: killall5 Not tainted 3.11.0-rc3-00288-gabe0308 #53
task: e90acac0 ti: e9be8000 task.ti: e9be8000
PC is at special_mapping_fault+0xa4/0xc4
LR is at __do_fault+0x68/0x48c
This doesn't show up unless you do quite a bit of testing; a simple
boot test does not do this, so all my nightly tests were passing fine.
The reason for this is that install_special_mapping() expects the
page array to stick around, and as this was only inserting one page
which was stored on the kernel stack, that's why this was blowing up.
Change-Id: Ib2cf8c19833e17d8d145e29141d68aaefd4dc233
Reported-by: Olof Johansson <olof@lixom.net>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: e0d407564b532d978b03ceccebd224a05d02f111
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index dd8c63d..0e78e9c 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -723,17 +723,18 @@
return NULL;
}
+static struct page *signal_page;
extern struct page *get_signal_page(void);
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct mm_struct *mm = current->mm;
- struct page *page;
unsigned long addr;
int ret;
- page = get_signal_page();
- if (!page)
+ if (!signal_page)
+ signal_page = get_signal_page();
+ if (!signal_page)
return -ENOMEM;
down_write(&mm->mmap_sem);
@@ -745,7 +746,7 @@
ret = install_special_mapping(mm, addr, PAGE_SIZE,
VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
- &page);
+ &signal_page);
if (ret == 0)
mm->context.sigpage = addr;