Commit-ID: d9f5f32a7d17f4906a21ad59589853639a1328a0 Gitweb: http://git.kernel.org/tip/d9f5f32a7d17f4906a21ad59589853639a1328a0 Author: Masami Hiramatsu <mhira...@kernel.org> AuthorDate: Thu, 3 Aug 2017 11:39:26 +0900 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 10 Aug 2017 16:28:53 +0200
kprobes/x86: Do not jump-optimize kprobes on irq entry code Since the kernel segment registers are not prepared at the entry of irq-entry code, if a kprobe on such code is jump-optimized, accessing per-CPU variables may cause a kernel panic. However, if the kprobe is not optimized, it triggers an int3 exception and sets segment registers correctly. With this patch we check the probe-address and if it is in the irq-entry code, it prohibits optimizing such kprobes. This means we can continue probing such interrupt handlers by kprobes but it is not optimized anymore. Reported-by: Francis Deslauriers <francis.deslauri...@efficios.com> Tested-by: Francis Deslauriers <francis.deslauri...@efficios.com> Signed-off-by: Masami Hiramatsu <mhira...@kernel.org> Cc: Ananth N Mavinakayanahalli <ana...@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamur...@intel.com> Cc: Chris Zankel <ch...@zankel.net> Cc: David S . Miller <da...@davemloft.net> Cc: Jesper Nilsson <jesper.nils...@axis.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Max Filippov <jcmvb...@gmail.com> Cc: Mikael Starvik <star...@axis.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Yoshinori Sato <ys...@users.sourceforge.jp> Cc: linux-a...@vger.kernel.org Cc: linux-cris-ker...@axis.com Cc: mathieu.desnoy...@efficios.com Link: http://lkml.kernel.org/r/150172795654.27216.9824039077047777477.stgit@devbox Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/kernel/kprobes/opt.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 69ea0bc..4f98aad 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -39,6 +39,7 @@ #include <asm/insn.h> #include <asm/debugreg.h> #include <asm/set_memory.h> +#include <asm/sections.h> #include "common.h" @@ -251,10 +252,12 @@ static int can_optimize(unsigned long paddr) /* * Do not optimize in the entry code due to the unstable - * stack handling. + * stack handling and registers setup. */ - if ((paddr >= (unsigned long)__entry_text_start) && - (paddr < (unsigned long)__entry_text_end)) + if (((paddr >= (unsigned long)__entry_text_start) && + (paddr < (unsigned long)__entry_text_end)) || + ((paddr >= (unsigned long)__irqentry_text_start) && + (paddr < (unsigned long)__irqentry_text_end))) return 0; /* Check there is enough space for a relative jump. */
