From: Felix Fietkau <nbd@nbd.name>
Date: Wed, 15 Feb 2017 11:33:03 +0000 (+0100)
Subject: kernel: fix crashes on MIPS when loading kernel modules under memory pressure
X-Git-Tag: v17.01.0~27
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=853bad5af293c6291894892237ddecbd24e370c8;p=openwrt%2Fopenwrt.git

kernel: fix crashes on MIPS when loading kernel modules under memory pressure

When memory is tight, modules may need to be loaded into vmalloc()
space. The code then has to generate jump trampolines which enable
relocations between vmalloc space and physical address space.

The code had a bug that was freeing these trampolines even when the
module was successfully loaded.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

diff --git a/target/linux/generic/patches-3.18/305-mips_module_reloc.patch b/target/linux/generic/patches-3.18/305-mips_module_reloc.patch
index f8ca91401a..fae7e70f0e 100644
--- a/target/linux/generic/patches-3.18/305-mips_module_reloc.patch
+++ b/target/linux/generic/patches-3.18/305-mips_module_reloc.patch
@@ -317,7 +317,7 @@
  
  	return 0;
  }
-@@ -287,9 +529,33 @@ int module_finalize(const Elf_Ehdr *hdr,
+@@ -287,9 +529,36 @@ int module_finalize(const Elf_Ehdr *hdr,
  		list_add(&me->arch.dbe_list, &dbe_list);
  		spin_unlock_irq(&dbe_lock);
  	}
@@ -338,6 +338,9 @@
  
 +void module_arch_freeing_init(struct module *mod)
 +{
++	if (mod->state == MODULE_STATE_LIVE)
++		return;
++
 +	if (mod->arch.phys_plt_tbl) {
 +		__module_free(mod->arch.phys_plt_tbl);
 +		mod->arch.phys_plt_tbl = NULL;
diff --git a/target/linux/generic/patches-4.4/305-mips_module_reloc.patch b/target/linux/generic/patches-4.4/305-mips_module_reloc.patch
index 8b3975fe09..944921fff7 100644
--- a/target/linux/generic/patches-4.4/305-mips_module_reloc.patch
+++ b/target/linux/generic/patches-4.4/305-mips_module_reloc.patch
@@ -316,7 +316,7 @@
  
  	return 0;
  }
-@@ -287,9 +528,33 @@ int module_finalize(const Elf_Ehdr *hdr,
+@@ -287,9 +528,36 @@ int module_finalize(const Elf_Ehdr *hdr,
  		list_add(&me->arch.dbe_list, &dbe_list);
  		spin_unlock_irq(&dbe_lock);
  	}
@@ -337,6 +337,9 @@
  
 +void module_arch_freeing_init(struct module *mod)
 +{
++	if (mod->state == MODULE_STATE_LIVE)
++		return;
++
 +	if (mod->arch.phys_plt_tbl) {
 +		__module_free(mod->arch.phys_plt_tbl);
 +		mod->arch.phys_plt_tbl = NULL;