Oops, forgot to tell it's for 4.9. Resending with proper subject.

Le 15/05/2019 à 08:39, Christophe Leroy a écrit :

[Backport of upstream commit b45ba4a51cde29b2939365ef0c07ad34c8321789]

On powerpc32, patch_instruction() is called by apply_feature_fixups() which is called from early_init()

There is the following note in front of early_init():

• Note that the kernel may be running at an address which is different
• from the address that it was linked at, so we must use RELOC/PTRRELOC
• to access static data (including strings). -- paulus

Therefore init_mem_is_free must be accessed with PTRRELOC()

Fixes: 1c38a84d4586 ("powerpc: Avoid code patching freed init sections") Link: https://bugzilla.kernel.org/show_bug.cgi?id=203597 Signed-off-by: Christophe Leroy christophe.leroy@c-s.fr

---

Can't apply the upstream commit as such due to several other unrelated stuff like for instance STRICT_KERNEL_RWX which are missing. So instead, using same approach as for commit 252eb55816a6f69ef9464cad303cdb3326cdc61d

---

arch/powerpc/lib/code-patching.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 14535ad4cdd1..c312955977ce 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -23,7 +23,7 @@ int patch_instruction(unsigned int *addr, unsigned int instr) int err; /* Make sure we aren't patching a freed init section */

• if (init_mem_is_free && init_section_contains(addr, 4)) {

• if (*PTRRELOC(&init_mem_is_free) && init_section_contains(addr, 4)) { pr_debug("Skipping init section patching addr: 0x%px\n", addr); return 0; }