user/sven/linux.git/arch/x86/kernel/dumpstack.c, branch v4.9.2

x86/dumpstack: Prevent KASAN false positive warnings

2016-11-18T08:38:00Z

The oops stack dump code scans the entire stack, which can cause KASAN "stack-out-of-bounds" false positive warnings. Tell KASAN to ignore it. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: davej@codemonkey.org.uk Cc: dvyukov@google.com Link: http://lkml.kernel.org/r/5f6e80c4b0c7f7f0b6211900847a247cdaad753c.1479398226.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar

x86/dumpstack: Fix show_stack() task pointer regression

2016-09-20T21:36:37Z

With the following commit: e18bcccd1a4e ("x86/dumpstack: Convert show_trace_log_lvl() to use the new unwinder") The task pointer argument to show_stack_log_lvl() in show_stack() was inadvertently changed to 'current'. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: byungchul.park@lge.com Cc: fweisbec@gmail.com Cc: keescook@chromium.org Cc: linux-tip-commits@vger.kernel.org Cc: luto@amacapital.net Cc: nilayvaish@gmail.com Cc: rostedt@goodmis.org Cc: tip-bot for Josh Poimboeuf Fixes: e18bcccd1a4e ("x86/dumpstack: Convert show_trace_log_lvl() to use the new unwinder") Link: http://lkml.kernel.org/r/20160920155340.yhewlx7vmgmov5fb@treble Signed-off-by: Ingo Molnar

x86/dumpstack: Remove dump_trace() and related callbacks

2016-09-20T06:29:34Z

All previous users of dump_trace() have been converted to use the new unwind interfaces, so we can remove it and the related print_context_stack() and print_context_stack_bp() callback functions. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Byungchul Park Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/5b97da3572b40b5a4d8e185cf2429308d0987a13.1474045023.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar

x86/dumpstack: Convert show_trace_log_lvl() to use the new unwinder

2016-09-20T06:29:34Z

Convert show_trace_log_lvl() to use the new unwinder. dump_trace() has been deprecated. show_trace_log_lvl() is special compared to other users of the unwinder. It's the only place where both reliable *and* unreliable addresses are needed. With frame pointers enabled, most callers of the unwinder don't want to know about unreliable addresses. But in this case, when we're dumping the stack to the console because something presumably went wrong, the unreliable addresses are useful: - They show stale data on the stack which can provide useful clues. - If something goes wrong with the unwinder, or if frame pointers are corrupt or missing, all the stack addresses still get shown. So in order to show all addresses on the stack, and at the same time figure out which addresses are reliable, we have to do the scanning and the unwinding in parallel. The scanning is done with the help of get_stack_info() to traverse the stacks. The unwinding is done separately by the new unwinder. In theory we could simplify show_trace_log_lvl() by instead pushing some of this logic into the unwind code. But then we would need some kind of "fake" frame logic in the unwinder which would add a lot of complexity and wouldn't be worth it in order to support only one user. Another benefit of this approach is that once we have a DWARF unwinder, we should be able to just plug it in with minimal impact to this code. Another change here is that callers of show_trace_log_lvl() don't need to provide the 'bp' argument. The unwinder already finds the relevant frame pointer by unwinding until it reaches the first frame after the provided stack pointer. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Byungchul Park Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/703b5998604c712a1f801874b43f35d6dac52ede.1474045023.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar

x86/dumpstack: Remove NULL task pointer convention

2016-09-16T14:21:39Z

show_stack_log_lvl() and friends allow a NULL pointer for the task_struct to indicate the current task. This creates confusion and can cause sneaky bugs. Instead require the caller to pass 'current' directly. This only changes the internal workings of the dumpstack code. The dump_trace() and show_stack() interfaces still allow a NULL task pointer. Those interfaces should also probably be fixed as well. Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/dumpstack: Add get_stack_info() interface

2016-09-15T06:13:15Z

valid_stack_ptr() is buggy: it assumes that all stacks are of size THREAD_SIZE, which is not true for exception stacks. So the walk_stack() callbacks will need to know the location of the beginning of the stack as well as the end. Another issue is that in general the various features of a stack (type, size, next stack pointer, description string) are scattered around in various places throughout the stack dump code. Encapsulate all that information in a single place with a new stack_info struct and a get_stack_info() interface. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Byungchul Park Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/8164dd0db96b7e6a279fa17ae5e6dc375eecb4a9.1473905218.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar

x86/dumpstack: Remove unnecessary stack pointer arguments

2016-09-08T06:58:40Z

When calling show_stack_log_lvl() or dump_trace() with a regs argument, providing a stack pointer or frame pointer is redundant. Signed-off-by: Josh Poimboeuf d Reviewed-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Brian Gerst Cc: Byungchul Park Cc: Frederic Weisbecker Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1694e2e955e3b9a73a3c3d5ba2634344014dd550.1472057064.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar

x86/dumpstack: Add get_stack_pointer() and get_frame_pointer()

2016-09-08T06:58:40Z

The various functions involved in dumping the stack all do similar things with regard to getting the stack pointer and the frame pointer based on the regs and task arguments. Create helper functions to do that instead. Signed-off-by: Josh Poimboeuf Reviewed-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Brian Gerst Cc: Byungchul Park Cc: Frederic Weisbecker Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/f448914885a35f333fe04da1b97a6c2cc1f80974.1472057064.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar

x86/dumpstack: Make printk_stack_address() more generally useful

2016-09-08T06:58:40Z

Change printk_stack_address() to be useful when called by an unwinder outside the context of dump_trace(). Specifically: - printk_stack_address()'s 'data' argument is always used as the log level string. Make that explicit. - Call touch_nmi_watchdog(). Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Brian Gerst Cc: Byungchul Park Cc: Frederic Weisbecker Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/9fbe0db05bacf66d337c162edbf61450d0cff1e2.1472057064.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar

x86/dumpstack/ftrace: Don't print unreliable addresses in print_context_stack_bp()

2016-08-24T10:15:15Z

When function graph tracing is enabled, print_context_stack_bp() can report return_to_handler() as an unreliable address, which is confusing and misleading: return_to_handler() is really only useful as a hint for debugging, whereas print_context_stack_bp() users only care about the actual 'reliable' call path. Signed-off-by: Josh Poimboeuf Acked-by: Steven Rostedt Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Byungchul Park Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/c51aef578d8027791b38d2ad9bac0c7f499fde91.1471607358.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar