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authorJosh Poimboeuf <jpoimboe@redhat.com>2016-09-14 22:07:44 -0400
committerIngo Molnar <mingo@kernel.org>2016-09-15 02:13:15 -0400
commitfcd709ef20a9d83bdb7524d27cd6719dac8690a0 (patch)
tree10a1653fa1da45343b11311c0c4336f77c4f4180 /arch/x86/kernel/dumpstack_32.c
parent5fe599e02e41550c59831613a11c8ae057897c29 (diff)
x86/dumpstack: Add recursion checking for all stacks
in_exception_stack() has some recursion checking which makes sure the stack trace code never traverses a given exception stack more than once. This prevents an infinite loop if corruption somehow causes a stack's "next stack" pointer to point to itself (directly or indirectly). The recursion checking can be useful for other stacks in addition to the exception stack, so extend it to work for all stacks. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nilay Vaish <nilayvaish@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/95de5db4cfe111754845a5cef04e20630d01423f.1473905218.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/dumpstack_32.c')
-rw-r--r--arch/x86/kernel/dumpstack_32.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 50076d4366c4..2d65cfa5e0b4 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -89,16 +89,32 @@ int get_stack_info(unsigned long *stack, struct task_struct *task,
89 task = task ? : current; 89 task = task ? : current;
90 90
91 if (in_task_stack(stack, task, info)) 91 if (in_task_stack(stack, task, info))
92 return 0; 92 goto recursion_check;
93 93
94 if (task != current) 94 if (task != current)
95 goto unknown; 95 goto unknown;
96 96
97 if (in_hardirq_stack(stack, info)) 97 if (in_hardirq_stack(stack, info))
98 return 0; 98 goto recursion_check;
99 99
100 if (in_softirq_stack(stack, info)) 100 if (in_softirq_stack(stack, info))
101 return 0; 101 goto recursion_check;
102
103 goto unknown;
104
105recursion_check:
106 /*
107 * Make sure we don't iterate through any given stack more than once.
108 * If it comes up a second time then there's something wrong going on:
109 * just break out and report an unknown stack type.
110 */
111 if (visit_mask) {
112 if (*visit_mask & (1UL << info->type))
113 goto unknown;
114 *visit_mask |= 1UL << info->type;
115 }
116
117 return 0;
102 118
103unknown: 119unknown:
104 info->type = STACK_TYPE_UNKNOWN; 120 info->type = STACK_TYPE_UNKNOWN;