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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-08-03 11:30:05 +0200 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-08-03 11:30:05 +0200 |
| commit | e0d407564b532d978b03ceccebd224a05d02f111 (patch) | |
| tree | fe3149db4e412e4f1d1e11941fcc260c0e5d287e /arch/arm/kernel/process.c | |
| parent | ARM: make vectors page inaccessible from userspace (diff) | |
| download | linux-e0d407564b532d978b03ceccebd224a05d02f111.tar.xz linux-e0d407564b532d978b03ceccebd224a05d02f111.zip | |
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.
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>
Diffstat (limited to 'arch/arm/kernel/process.c')
| -rw-r--r-- | arch/arm/kernel/process.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 1e6c33d01c05..d03b5bd889c5 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -471,17 +471,18 @@ const char *arch_vma_name(struct vm_area_struct *vma) "[sigpage]" : 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); @@ -493,7 +494,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 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; |