From: Christophe Leroy christophe.leroy@csgroup.eu
[ Upstream commit d9ab6da64fd15608c9feb20d769d8df1a32fe212 ]
That test was introducted in 2006 by commit 00ae36de49cc ("[POWERPC] Better check in show_instructions"). At that time, there was no BPF progs.
As seen in message of commit 89d21e259a94 ("powerpc/bpf/32: Fix Oops on tail call tests"), when a page fault occurs in test_bpf.ko for instance, the code is dumped as XXXXXXXXs. Allthough __kernel_text_address() checks is_bpf_text_address(), it seems it is not enough.
Today, show_instructions() uses get_kernel_nofault() to read the code, so there is no real need for additional verifications.
ARM64 and x86 don't do any additional check before dumping instructions. Do the same and remove __kernel_text_address() in show_instructions().
Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/4fd69ef7945518c3e27f96b95046a5c1468d35bf.167524577... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/process.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index c22cc234672f9..effe9697905dc 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1405,8 +1405,7 @@ static void show_instructions(struct pt_regs *regs) for (i = 0; i < NR_INSN_TO_PRINT; i++) { int instr;
- if (!__kernel_text_address(pc) || - get_kernel_nofault(instr, (const void *)pc)) { + if (get_kernel_nofault(instr, (const void *)pc)) { pr_cont("XXXXXXXX "); } else { if (nip == pc)