[PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it

[Andy Lutomirski]

This will help debug OOPSes related to USER_DS vs KERNEL_DS.

Signed-off-by: Andy Lutomirski <l...@kernel.org>
---
 arch/x86/kernel/dumpstack_32.c | 4 ++++
 arch/x86/kernel/dumpstack_64.c | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 464ffd69b92e..5dbb08fd8291 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -124,8 +124,12 @@ show_stack_log_lvl(struct task_struct *task, struct 
pt_regs *regs,
 void show_regs(struct pt_regs *regs)
 {
        int i;
+       struct thread_info *ti = current_thread_info();
 
        show_regs_print_info(KERN_EMERG);
+       if (ti->addr_limit.seg != TASK_SIZE_MAX)
+               printk(KERN_DEFAULT "task.addr_limit: 0x%lx\n",
+                      ti->addr_limit.seg);
        __show_regs(regs, !user_mode(regs));
 
        /*
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 5f1c6266eb30..2fdeb64dfed0 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -301,9 +301,14 @@ void show_regs(struct pt_regs *regs)
 {
        int i;
        unsigned long sp;
+       struct thread_info *ti = current_thread_info();
 
        sp = regs->sp;
+
        show_regs_print_info(KERN_DEFAULT);
+       if (ti->addr_limit.seg != TASK_SIZE_MAX)
+               printk(KERN_DEFAULT "task.addr_limit: 0x%lx\n",
+                      ti->addr_limit.seg);
        __show_regs(regs, 1);
 
        /*
-- 
2.5.5