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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-10-30 20:42:09 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-11-01 15:51:03 +1100 |
| commit | e6c4dcb308160115287afd87afb63b5684d75a5b (patch) | |
| tree | 39f5d7025289979f52bf1c787db5102f2889995d /arch | |
| parent | 63be1a81e40733ecd175713b6a7558dc43f00851 (diff) | |
| download | linux-e6c4dcb308160115287afd87afb63b5684d75a5b.tar.bz2 | |
powerpc/kprobes: Dereference function pointers only if the address does not belong to kernel text
This makes the changes introduced in commit 83e840c770f2c5
("powerpc64/elfv1: Only dereference function descriptor for non-text
symbols") to be specific to the kprobe subsystem.
We previously changed ppc_function_entry() to always check the provided
address to confirm if it needed to be dereferenced. This is actually
only an issue for kprobe blacklisted asm labels (through use of
_ASM_NOKPROBE_SYMBOL) and can cause other issues with ftrace. Also, the
additional checks are not really necessary for our other uses.
As such, move this check to the kprobes subsystem.
Fixes: 83e840c770f2 ("powerpc64/elfv1: Only dereference function descriptor for non-text symbols")
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/kprobes.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 367494dc67d9..bebc3007a793 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -600,7 +600,12 @@ NOKPROBE_SYMBOL(kprobe_fault_handler); unsigned long arch_deref_entry_point(void *entry) { - return ppc_global_function_entry(entry); +#ifdef PPC64_ELF_ABI_v1 + if (!kernel_text_address((unsigned long)entry)) + return ppc_global_function_entry(entry); + else +#endif + return (unsigned long)entry; } NOKPROBE_SYMBOL(arch_deref_entry_point); |