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| author | Andy Lutomirski <luto@kernel.org> | 2015-07-31 05:32:42 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-08-04 10:16:55 +0200 |
| commit | 27747f8bc355a2808ca9e490ab6866acd85b4c16 (patch) | |
| tree | 27a6a89c2e8497cdf79e461e1084fb872e62987c /arch/x86/kernel/hw_breakpoint.c | |
| parent | perf/x86/hw_breakpoints: Improve range breakpoint validation (diff) | |
| download | linux-27747f8bc355a2808ca9e490ab6866acd85b4c16.tar.xz linux-27747f8bc355a2808ca9e490ab6866acd85b4c16.zip | |
perf/x86/hw_breakpoints: Fix check for kernel-space breakpoints
The check looked wrong, although I think it was actually safe. TASK_SIZE
is unnecessarily small for compat tasks, and it wasn't possible to make
a range breakpoint so large it started in user space and ended in kernel
space.
Nonetheless, let's fix up the check for the benefit of future
readers. A breakpoint is in the kernel if either end is in the
kernel.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.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/136be387950e78f18cea60e9d1bef74465d0ee8f.1438312874.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/hw_breakpoint.c')
| -rw-r--r-- | arch/x86/kernel/hw_breakpoint.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index 6f345d302cf6..50a3fad5b89f 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -180,7 +180,11 @@ int arch_check_bp_in_kernelspace(struct perf_event *bp) va = info->address; len = bp->attr.bp_len; - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + /* + * We don't need to worry about va + len - 1 overflowing: + * we already require that va is aligned to a multiple of len. + */ + return (va >= TASK_SIZE_MAX) || ((va + len - 1) >= TASK_SIZE_MAX); } int arch_bp_generic_fields(int x86_len, int x86_type, |