linux/kernel/kprobes.c, branch v3.18

kprobes: Skip kretprobe hit in NMI context to avoid deadlock

2014-08-08T08:38:04Z

Skip kretprobe hit in NMI context, because if an NMI happens inside the critical section protected by kretprobe_table.lock and another(or same) kretprobe hit, pre_kretprobe_handler tries to lock kretprobe_table.lock again. Normal interrupts have no problem because they are disabled with the lock. Signed-off-by: Masami Hiramatsu Acked-by: Ananth N Mavinakayanahalli Cc: David S. Miller Link: http://lkml.kernel.org/r/20140804031016.11433.65539.stgit@kbuild-fedora.novalocal [ Minor edits for clarity. ] Signed-off-by: Ingo Molnar

kprobes: Fix "Failed to find blacklist" probing errors on ia64 and ppc64

2014-07-18T04:23:40Z

On ia64 and ppc64, function pointers do not point to the entry address of the function, but to the address of a function descriptor (which contains the entry address and misc data). Since the kprobes code passes the function pointer stored by NOKPROBE_SYMBOL() to kallsyms_lookup_size_offset() for initalizing its blacklist, it fails and reports many errors, such as: Failed to find blacklist 0001013168300000 Failed to find blacklist 0001013000f0a000 [...] To fix this bug, use arch_deref_entry_point() to get the function entry address for kallsyms_lookup_size_offset() instead of the raw function pointer. Suzuki also pointed out that blacklist entries should also be updated as well. Reported-by: Tony Luck Fixed-by: Suzuki K. Poulose Tested-by: Tony Luck Tested-by: Michael Ellerman Signed-off-by: Masami Hiramatsu Acked-by: Michael Ellerman (for powerpc) Acked-by: Benjamin Herrenschmidt Cc: Jeremy Fitzhardinge Cc: sparse@chrisli.org Cc: Paul Mackerras Cc: akataria@vmware.com Cc: anil.s.keshavamurthy@intel.com Cc: Fenghua Yu Cc: Arnd Bergmann Cc: Rusty Russell Cc: Chris Wright Cc: yrl.pp-manager.tt@hitachi.com Cc: Kevin Hao Cc: Ananth N Mavinakayanahalli Cc: rdunlap@infradead.org Cc: dl9pf@gmx.de Cc: Linus Torvalds Cc: David S. Miller Cc: linux-ia64@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20140717114411.13401.2632.stgit@kbuild-fedora.novalocal Signed-off-by: Ingo Molnar

kprobes: Show blacklist entries via debugfs

2014-04-24T08:26:41Z

Show blacklist entries (function names with the address range) via /sys/kernel/debug/kprobes/blacklist. Note that at this point the blacklist supports only in vmlinux, not module. So the list is fixed and not updated. Signed-off-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Cc: David S. Miller Link: http://lkml.kernel.org/r/20140417081849.26341.11609.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar

kprobes: Use NOKPROBE_SYMBOL macro instead of __kprobes

2014-04-24T08:26:38Z

Use NOKPROBE_SYMBOL macro to protect functions from kprobes instead of __kprobes annotation. Signed-off-by: Masami Hiramatsu Reviewed-by: Steven Rostedt Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Cc: David S. Miller Link: http://lkml.kernel.org/r/20140417081821.26341.40362.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar

kprobes: Allow probe on some kprobe functions

2014-04-24T08:03:01Z

There is no need to prohibit probing on the functions used for preparation, registeration, optimization, controll etc. Those are safely probed because those are not invoked from breakpoint/fault/debug handlers, there is no chance to cause recursive exceptions. Following functions are now removed from the kprobes blacklist: add_new_kprobe aggr_kprobe_disabled alloc_aggr_kprobe alloc_aggr_kprobe arm_all_kprobes __arm_kprobe arm_kprobe arm_kprobe_ftrace check_kprobe_address_safe collect_garbage_slots collect_garbage_slots collect_one_slot debugfs_kprobe_init __disable_kprobe disable_kprobe disarm_all_kprobes __disarm_kprobe disarm_kprobe disarm_kprobe_ftrace do_free_cleaned_kprobes do_optimize_kprobes do_unoptimize_kprobes enable_kprobe force_unoptimize_kprobe free_aggr_kprobe free_aggr_kprobe __free_insn_slot __get_insn_slot get_optimized_kprobe __get_valid_kprobe init_aggr_kprobe init_aggr_kprobe in_nokprobe_functions kick_kprobe_optimizer kill_kprobe kill_optimized_kprobe kprobe_addr kprobe_optimizer kprobe_queued kprobe_seq_next kprobe_seq_start kprobe_seq_stop kprobes_module_callback kprobes_open optimize_all_kprobes optimize_kprobe prepare_kprobe prepare_optimized_kprobe register_aggr_kprobe register_jprobe register_jprobes register_kprobe register_kprobes register_kretprobe register_kretprobe register_kretprobes register_kretprobes report_probe show_kprobe_addr try_to_optimize_kprobe unoptimize_all_kprobes unoptimize_kprobe unregister_jprobe unregister_jprobes unregister_kprobe __unregister_kprobe_bottom unregister_kprobes __unregister_kprobe_top unregister_kretprobe unregister_kretprobe unregister_kretprobes unregister_kretprobes wait_for_kprobe_optimizer I tested those functions by putting kprobes on all instructions in the functions with the bash script I sent to LKML. See: https://lkml.org/lkml/2014/3/27/33 Signed-off-by: Masami Hiramatsu Link: http://lkml.kernel.org/r/20140417081753.26341.57889.stgit@ltc230.yrl.intra.hitachi.co.jp Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Cc: David S. Miller Cc: fche@redhat.com Cc: systemtap@sourceware.org Signed-off-by: Ingo Molnar

kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist

2014-04-24T08:02:56Z

Introduce NOKPROBE_SYMBOL() macro which builds a kprobes blacklist at kernel build time. The usage of this macro is similar to EXPORT_SYMBOL(), placed after the function definition: NOKPROBE_SYMBOL(function); Since this macro will inhibit inlining of static/inline functions, this patch also introduces a nokprobe_inline macro for static/inline functions. In this case, we must use NOKPROBE_SYMBOL() for the inline function caller. When CONFIG_KPROBES=y, the macro stores the given function address in the "_kprobe_blacklist" section. Since the data structures are not fully initialized by the macro (because there is no "size" information), those are re-initialized at boot time by using kallsyms. Signed-off-by: Masami Hiramatsu Link: http://lkml.kernel.org/r/20140417081705.26341.96719.stgit@ltc230.yrl.intra.hitachi.co.jp Cc: Alok Kataria Cc: Ananth N Mavinakayanahalli Cc: Andrew Morton Cc: Anil S Keshavamurthy Cc: Arnd Bergmann Cc: Christopher Li Cc: Chris Wright Cc: David S. Miller Cc: Jan-Simon Möller Cc: Jeremy Fitzhardinge Cc: Linus Torvalds Cc: Randy Dunlap Cc: Rusty Russell Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-sparse@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Signed-off-by: Ingo Molnar

kprobes: Prohibit probing on .entry.text code

2014-04-24T08:02:56Z

.entry.text is a code area which is used for interrupt/syscall entries, which includes many sensitive code. Thus, it is better to prohibit probing on all of such code instead of a part of that. Since some symbols are already registered on kprobe blacklist, this also removes them from the blacklist. Signed-off-by: Masami Hiramatsu Reviewed-by: Steven Rostedt Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Cc: Borislav Petkov Cc: David S. Miller Cc: Frederic Weisbecker Cc: Jan Kiszka Cc: Jiri Kosina Cc: Jonathan Lebon Cc: Seiji Aguchi Link: http://lkml.kernel.org/r/20140417081658.26341.57354.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar

kprobes: use KSYM_NAME_LEN to size identifier buffers

2013-11-13T03:09:26Z

Use KSYM_NAME_LEN to size identifier buffers, so that it can be easier increased. Signed-off-by: Joe Mario Signed-off-by: Andi Kleen Acked-by: Ananth N Mavinakayanahalli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kprobes: allow to specify custom allocator for insn caches

2013-09-11T22:58:52Z

The current two insn slot caches both use module_alloc/module_free to allocate and free insn slot cache pages. For s390 this is not sufficient since there is the need to allocate insn slots that are either within the vmalloc module area or within dma memory. Therefore add a mechanism which allows to specify an own allocator for an own insn slot cache. Signed-off-by: Heiko Carstens Acked-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Ingo Molnar Cc: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kprobes: unify insn caches

2013-09-11T22:58:52Z

The current kpropes insn caches allocate memory areas for insn slots with module_alloc(). The assumption is that the kernel image and module area are both within the same +/- 2GB memory area. This however is not true for s390 where the kernel image resides within the first 2GB (DMA memory area), but the module area is far away in the vmalloc area, usually somewhere close below the 4TB area. For new pc relative instructions s390 needs insn slots that are within +/- 2GB of each area. That way we can patch displacements of pc-relative instructions within the insn slots just like x86 and powerpc. The module area works already with the normal insn slot allocator, however there is currently no way to get insn slots that are within the first 2GB on s390 (aka DMA area). Therefore this patch set modifies the kprobes insn slot cache code in order to allow to specify a custom allocator for the insn slot cache pages. In addition architecure can now have private insn slot caches withhout the need to modify common code. Patch 1 unifies and simplifies the current insn and optinsn caches implementation. This is a preparation which allows to add more insn caches in a simple way. Patch 2 adds the possibility to specify a custom allocator. Patch 3 makes s390 use the new insn slot mechanisms and adds support for pc-relative instructions with long displacements. This patch (of 3): The two insn caches (insn, and optinsn) each have an own mutex and alloc/free functions (get_[opt]insn_slot() / free_[opt]insn_slot()). Since there is the need for yet another insn cache which satifies dma allocations on s390, unify and simplify the current implementation: - Move the per insn cache mutex into struct kprobe_insn_cache. - Move the alloc/free functions to kprobe.h so they are simply wrappers for the generic __get_insn_slot/__free_insn_slot functions. The implementation is done with a DEFINE_INSN_CACHE_OPS() macro which provides the alloc/free functions for each cache if needed. - move the struct kprobe_insn_cache to kprobe.h which allows to generate architecture specific insn slot caches outside of the core kprobes code. Signed-off-by: Heiko Carstens Cc: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Ingo Molnar Cc: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds