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

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/1e1a0592f8309a8253e39d0f6a42193e60d80d23

commit 1e1a0592f8309a8253e39d0f6a42193e60d80d23
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Wed Feb 15 12:33:03 2017 +0100

    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 at nbd.name>
---
 target/linux/generic/patches-3.18/305-mips_module_reloc.patch | 5 ++++-
 target/linux/generic/patches-4.4/305-mips_module_reloc.patch  | 5 ++++-
 target/linux/generic/patches-4.9/305-mips_module_reloc.patch  | 5 ++++-
 3 files changed, 12 insertions(+), 3 deletions(-)

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 f8ca914..fae7e70 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 8b3975f..944921f 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;
diff --git a/target/linux/generic/patches-4.9/305-mips_module_reloc.patch b/target/linux/generic/patches-4.9/305-mips_module_reloc.patch
index 997105b..1c2bd0a 100644
--- a/target/linux/generic/patches-4.9/305-mips_module_reloc.patch
+++ b/target/linux/generic/patches-4.9/305-mips_module_reloc.patch
@@ -315,7 +315,7 @@
  
  	return 0;
  }
-@@ -349,9 +591,33 @@ int module_finalize(const Elf_Ehdr *hdr,
+@@ -349,9 +591,36 @@ int module_finalize(const Elf_Ehdr *hdr,
  		list_add(&me->arch.dbe_list, &dbe_list);
  		spin_unlock_irq(&dbe_lock);
  	}
@@ -336,6 +336,9 @@
  
 +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;