Messages in this thread Patch in this message | | | Date | Mon, 29 Feb 2016 03:02:18 -0800 | From | tip-bot for Oleg Nesterov <> | Subject | [tip:x86/asm] uprobes: __create_xol_area() must nullify xol_mapping.fault |
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Commit-ID: 869ae76147ffdf21ad24f0e599303cd58a2bb39f Gitweb: http://git.kernel.org/tip/869ae76147ffdf21ad24f0e599303cd58a2bb39f Author: Oleg Nesterov <oleg@redhat.com> AuthorDate: Sat, 27 Feb 2016 23:11:28 +0100 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Mon, 29 Feb 2016 08:47:51 +0100
uprobes: __create_xol_area() must nullify xol_mapping.fault
As Jiri pointed out, this recent commit:
f872f5400cc0 ("mm: Add a vm_special_mapping.fault() method")
breaks uprobes: __create_xol_area() doesn't initialize the new ->fault() method and this obviously leads to kernel crash when the application tries to execute the probed insn after bp hit.
We probably want to add uprobes_special_mapping_fault(), this allows to turn xol_area->xol_mapping into a single instance of vm_special_mapping. But we need a simple fix, so lets change __create_xol() to nullify the new member as Jiri suggests.
Suggested-by: Jiri Olsa <jolsa@redhat.com> Reported-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <tipbot@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pratyush Anand <panand@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160227221128.GA29565@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/events/uprobes.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 0167679..5f6ce93 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1178,6 +1178,7 @@ static struct xol_area *__create_xol_area(unsigned long vaddr) goto free_area; area->xol_mapping.name = "[uprobes]"; + area->xol_mapping.fault = NULL; area->xol_mapping.pages = area->pages; area->pages[0] = alloc_page(GFP_HIGHUSER); if (!area->pages[0])
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