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* x86: Fix compilation bug in kprobes' twobyte_is_boostableJosh Stone2011-11-111-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 315eb8a2a1b7f335d40ceeeb11b9e067475eb881 upstream. When compiling an i386_defconfig kernel with gcc-4.6.1-9.fc15.i686, I noticed a warning about the asm operand for test_bit in kprobes' can_boost. I discovered that this caused only the first long of twobyte_is_boostable[] to be output. Jakub filed and fixed gcc PR50571 to correct the warning and this output issue. But to solve it for less current gcc, we can make kprobes' twobyte_is_boostable[] non-const, and it won't be optimized out. Before: CC arch/x86/kernel/kprobes.o In file included from include/linux/bitops.h:22:0, from include/linux/kernel.h:17, from [...]/arch/x86/include/asm/percpu.h:44, from [...]/arch/x86/include/asm/current.h:5, from [...]/arch/x86/include/asm/processor.h:15, from [...]/arch/x86/include/asm/atomic.h:6, from include/linux/atomic.h:4, from include/linux/mutex.h:18, from include/linux/notifier.h:13, from include/linux/kprobes.h:34, from arch/x86/kernel/kprobes.c:43: [...]/arch/x86/include/asm/bitops.h: In function ‘can_boost.part.1’: [...]/arch/x86/include/asm/bitops.h:319:2: warning: use of memory input without lvalue in asm operand 1 is deprecated [enabled by default] $ objdump -rd arch/x86/kernel/kprobes.o | grep -A1 -w bt 551: 0f a3 05 00 00 00 00 bt %eax,0x0 554: R_386_32 .rodata.cst4 $ objdump -s -j .rodata.cst4 -j .data arch/x86/kernel/kprobes.o arch/x86/kernel/kprobes.o: file format elf32-i386 Contents of section .data: 0000 48000000 00000000 00000000 00000000 H............... Contents of section .rodata.cst4: 0000 4c030000 L... Only a single long of twobyte_is_boostable[] is in the object file. After, without the const on twobyte_is_boostable: $ objdump -rd arch/x86/kernel/kprobes.o | grep -A1 -w bt 551: 0f a3 05 20 00 00 00 bt %eax,0x20 554: R_386_32 .data $ objdump -s -j .rodata.cst4 -j .data arch/x86/kernel/kprobes.o arch/x86/kernel/kprobes.o: file format elf32-i386 Contents of section .data: 0000 48000000 00000000 00000000 00000000 H............... 0010 00000000 00000000 00000000 00000000 ................ 0020 4c030000 0f000200 ffff0000 ffcff0c0 L............... 0030 0000ffff 3bbbfff8 03ff2ebb 26bb2e77 ....;.......&..w Now all 32 bytes are output into .data instead. Signed-off-by: Josh Stone <jistone@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jakub Jelinek <jakub@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* kprobes, x86: Disable irqs during optimized callbackJiri Olsa2011-05-111-2/+3
| | | | | | | | | | | | | | | | | | | | Disable irqs during optimized callback, so we dont miss any in-irq kprobes. The following commands: # cd /debug/tracing/ # echo "p mutex_unlock" >> kprobe_events # echo "p _raw_spin_lock" >> kprobe_events # echo "p smp_apic_timer_interrupt" >> ./kprobe_events # echo 1 > events/enable Cause the optimized kprobes to be missed. None is missed with the fix applied. Signed-off-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Link: http://lkml.kernel.org/r/20110511110613.GB2390@jolsa.brq.redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes: Disabling optimized kprobes for entry text sectionJiri Olsa2011-03-081-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | You can crash the kernel (with root/admin privileges) using kprobe tracer by running: echo "p system_call_after_swapgs" > ./kprobe_events echo 1 > ./events/kprobes/enable The reason is that at the system_call_after_swapgs label, the kernel stack is not set up. If optimized kprobes are enabled, the user space stack is being used in this case (see optimized kprobe template) and this might result in a crash. There are several places like this over the entry code (entry_$BIT). As it seems there's no any reasonable/maintainable way to disable only those places where the stack is not ready, I switched off the whole entry code from kprobe optimizing. Signed-off-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: acme@redhat.com Cc: fweisbec@gmail.com Cc: ananth@in.ibm.com Cc: davem@davemloft.net Cc: a.p.zijlstra@chello.nl Cc: eric.dumazet@gmail.com Cc: 2nddept-manager@sdl.hitachi.co.jp LKML-Reference: <1298298313-5980-3-git-send-email-jolsa@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'for-2.6.38' of ↵Linus Torvalds2011-01-071-7/+7
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (30 commits) gameport: use this_cpu_read instead of lookup x86: udelay: Use this_cpu_read to avoid address calculation x86: Use this_cpu_inc_return for nmi counter x86: Replace uses of current_cpu_data with this_cpu ops x86: Use this_cpu_ops to optimize code vmstat: User per cpu atomics to avoid interrupt disable / enable irq_work: Use per cpu atomics instead of regular atomics cpuops: Use cmpxchg for xchg to avoid lock semantics x86: this_cpu_cmpxchg and this_cpu_xchg operations percpu: Generic this_cpu_cmpxchg() and this_cpu_xchg support percpu,x86: relocate this_cpu_add_return() and friends connector: Use this_cpu operations xen: Use this_cpu_inc_return taskstats: Use this_cpu_ops random: Use this_cpu_inc_return fs: Use this_cpu_inc_return in buffer.c highmem: Use this_cpu_xx_return() operations vmstat: Use this_cpu_inc_return for vm statistics x86: Support for this_cpu_add, sub, dec, inc_return percpu: Generic support for this_cpu_add, sub, dec, inc_return ... Fixed up conflicts: in arch/x86/kernel/{apic/nmi.c, apic/x2apic_uv_x.c, process.c} as per Tejun.
| * kprobes: Use this_cpu_opsChristoph Lameter2010-12-171-7/+7
| | | | | | | | | | | | | | | | | | | | Use this_cpu ops in various places to optimize per cpu data access. Cc: Jason Baron <jbaron@redhat.com> Cc: Namhyung Kim <namhyung@gmail.com> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | kprobes: Use text_poke_smp_batch for unoptimizingMasami Hiramatsu2010-12-061-0/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use text_poke_smp_batch() on unoptimization path for reducing the number of stop_machine() issues. If the number of unoptimizing probes is more than MAX_OPTIMIZE_PROBES(=256), kprobes unoptimizes first MAX_OPTIMIZE_PROBES probes and kicks optimizer for remaining probes. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: 2nddept-manager@sdl.hitachi.co.jp Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20101203095434.2961.22657.stgit@ltc236.sdl.hitachi.co.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | kprobes: Use text_poke_smp_batch for optimizingMasami Hiramatsu2010-12-061-8/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use text_poke_smp_batch() in optimization path for reducing the number of stop_machine() issues. If the number of optimizing probes is more than MAX_OPTIMIZE_PROBES(=256), kprobes optimizes first MAX_OPTIMIZE_PROBES probes and kicks optimizer for remaining probes. Changes in v5: - Use kick_kprobe_optimizer() instead of directly calling schedule_delayed_work(). - Rescheduling optimizer outside of kprobe mutex lock. Changes in v2: - Allocate code buffer and parameters in arch_init_kprobes() instead of using static arraies. - Merge previous max optimization limit patch into this patch. So, this patch introduces upper limit of optimization at once. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: 2nddept-manager@sdl.hitachi.co.jp Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20101203095428.2961.8994.stgit@ltc236.sdl.hitachi.co.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | kprobes: Support delayed unoptimizingMasami Hiramatsu2010-12-061-0/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | Unoptimization occurs when a probe is unregistered or disabled, and is heavy because it recovers instructions by using stop_machine(). This patch delays unoptimization operations and unoptimize several probes at once by using text_poke_smp_batch(). This can avoid unexpected system slowdown coming from stop_machine(). Changes in v5: - Split this patch into several cleanup patches and this patch. - Fix some text_mutex lock miss. - Use bool instead of int for behavior flags. - Add additional comment for (un)optimizing path. Changes in v2: - Use dynamic allocated buffers and params. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: 2nddept-manager@sdl.hitachi.co.jp LKML-Reference: <20101203095409.2961.82733.stgit@ltc236.sdl.hitachi.co.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* jump label: Add jump_label_text_reserved() to reserve jump pointsJason Baron2010-09-221-1/+2
| | | | | | | | | | | Add a jump_label_text_reserved(void *start, void *end), so that other pieces of code that want to modify kernel text, can first verify that jump label has not reserved the instruction. Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <06236663a3a7b1c1f13576bb9eccb6d9c17b7bfe.1284733808.git.jbaron@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* kprobes: Remove __dummy_bufNamhyung Kim2010-09-151-7/+2
| | | | | | | | | | Remove __dummy_buf which is needed for kallsyms_lookup only. use kallsysm_lookup_size_offset instead. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> LKML-Reference: <1284512670-2369-5-git-send-email-namhyung@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes: Make functions staticNamhyung Kim2010-09-151-1/+1
| | | | | | | | | | | | | | Make following (internal) functions static to make sparse happier :-) * get_optimized_kprobe: only called from static functions * kretprobe_table_unlock: _lock function is static * kprobes_optinsn_template_holder: never called but holding asm code Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> LKML-Reference: <1284512670-2369-4-git-send-email-namhyung@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes/x86: Fix the return address of multiple kretprobesKUMANO Syuhei2010-08-191-3/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix the return address of subsequent kretprobes when multiple kretprobes are set on the same function. For example: # cd /sys/kernel/debug/tracing # echo "r:event1 sys_symlink" > kprobe_events # echo "r:event2 sys_symlink" >> kprobe_events # echo 1 > events/kprobes/enable # ln -s /tmp/foo /tmp/bar (without this patch) # cat trace ln-897 [000] 20404.133727: event1: (kretprobe_trampoline+0x0/0x4c <- sys_symlink) ln-897 [000] 20404.133747: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink) (with this patch) # cat trace ln-740 [000] 13799.491076: event1: (system_call_fastpath+0x16/0x1b <- sys_symlink) ln-740 [000] 13799.491096: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink) Signed-off-by: KUMANO Syuhei <kumano.prog@gmail.com> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> LKML-Reference: <1281853084.3254.11.camel@camp10-laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'linus' into perf/coreIngo Molnar2010-07-211-1/+1
|\ | | | | | | | | | | Merge reason: Pick up the latest perf fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * x86: kprobes: fix swapped segment registers in kretprobeRoland McGrath2010-07-181-1/+1
| | | | | | | | | | | | | | | | | | In commit f007ea26, the order of the %es and %ds segment registers got accidentally swapped, so synthesized 'struct pt_regs' frames have the two values inverted. It's almost sure that these values never matter, and that they also never differ. But wrong is wrong. Signed-off-by: Roland McGrath <roland@redhat.com>
* | kprobes/x86: Fix kprobes to skip prefixes correctlyMasami Hiramatsu2010-06-291-16/+17
|/ | | | | | | | | | | | | | | | | | | | | | Fix resume_execution() and is_IF_modifier() to skip x86 instruction prefixes correctly by using x86 instruction attribute. Without this fix, resume_execution() can't handle instructions which have non-REX prefixes (REX prefixes are skipped). This will cause unexpected kernel panic by hitting bad address when a kprobe hits on two-byte ret (e.g. "repz ret" generated for Athlon/K8 optimization), because it just checks "repz" and can't recognize the "ret" instruction. These prefixes can be found easily with x86 instruction attribute. This patch introduces skip_prefixes() and uses it in resume_execution() and is_IF_modifier() to skip prefixes. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <4C298A6E.8070609@hitachi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2010-05-181-4/+12
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (311 commits) perf tools: Add mode to build without newt support perf symbols: symbol inconsistency message should be done only at verbose=1 perf tui: Add explicit -lslang option perf options: Type check all the remaining OPT_ variants perf options: Type check OPT_BOOLEAN and fix the offenders perf options: Check v type in OPT_U?INTEGER perf options: Introduce OPT_UINTEGER perf tui: Add workaround for slang < 2.1.4 perf record: Fix bug mismatch with -c option definition perf options: Introduce OPT_U64 perf tui: Add help window to show key associations perf tui: Make <- exit menus too perf newt: Add single key shortcuts for zoom into DSO and threads perf newt: Exit browser unconditionally when CTRL+C, q or Q is pressed perf newt: Fix the 'A'/'a' shortcut for annotate perf newt: Make <- exit the ui_browser x86, perf: P4 PMU - fix counters management logic perf newt: Make <- zoom out filters perf report: Report number of events, not samples perf hist: Clarify events_stats fields usage ... Fix up trivial conflicts in kernel/fork.c and tools/perf/builtin-record.c
| * x86, ptrace: Fix block-stepPeter Zijlstra2010-03-261-2/+12
| | | | | | | | | | | | | | | | | | | | Implement ptrace-block-step using TIF_BLOCKSTEP which will set DEBUGCTLMSR_BTF when set for a task while preserving any other DEBUGCTLMSR bits. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20100325135414.017536066@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * x86, perf, bts, mm: Delete the never used BTS-ptrace codePeter Zijlstra2010-03-261-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Support for the PMU's BTS features has been upstreamed in v2.6.32, but we still have the old and disabled ptrace-BTS, as Linus noticed it not so long ago. It's buggy: TIF_DEBUGCTLMSR is trampling all over that MSR without regard for other uses (perf) and doesn't provide the flexibility needed for perf either. Its users are ptrace-block-step and ptrace-bts, since ptrace-bts was never used and ptrace-block-step can be implemented using a much simpler approach. So axe all 3000 lines of it. That includes the *locked_memory*() APIs in mm/mlock.c as well. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Markus Metzger <markus.t.metzger@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20100325135413.938004390@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | kprobes/x86: Fix removed int3 checking orderMasami Hiramatsu2010-05-111-14/+13
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix kprobe/x86 to check removed int3 when failing to get kprobe from hlist. Since we have a time window between checking int3 exists on probed address and getting kprobe on that address, we can have following scenario: ------- CPU1 CPU2 hit int3 check int3 exists remove int3 remove kprobe from hlist get kprobe from hlist no kprobe->OOPS! ------- This patch moves int3 checking if there is no kprobe on that address for fixing this problem as follows: ------ CPU1 CPU2 hit int3 remove int3 remove kprobe from hlist get kprobe from hlist no kprobe->check int3 exists ->rollback&retry ------ Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Dave Anderson <anderson@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20100427223348.2322.9112.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes/x86: Support kprobes jump optimization on x86Masami Hiramatsu2010-02-251-22/+411
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce x86 arch-specific optimization code, which supports both of x86-32 and x86-64. This code also supports safety checking, which decodes whole of a function in which probe is inserted, and checks following conditions before optimization: - The optimized instructions which will be replaced by a jump instruction don't straddle the function boundary. - There is no indirect jump instruction, because it will jumps into the address range which is replaced by jump operand. - There is no jump/loop instruction which jumps into the address range which is replaced by jump operand. - Don't optimize kprobes if it is in functions into which fixup code will jumps. This uses text_poke_multibyte() which doesn't support modifying code on NMI/MCE handler. However, since kprobes itself doesn't support NMI/MCE code probing, it's not a problem. Changes in v9: - Use *_text_reserved() for checking the probe can be optimized. - Verify jump address range is in 2G range when preparing slot. - Backup original code when switching optimized buffer, instead of preparing buffer, because there can be int3 of other probes in preparing phase. - Check kprobe is disabled in arch_check_optimized_kprobe(). - Strictly check indirect jump opcodes (ff /4, ff /5). Changes in v6: - Split stop_machine-based jump patching code. - Update comments and coding style. Changes in v5: - Introduce stop_machine-based jump replacing. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133446.6725.78994.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes/x86: Cleanup save/restore registersMasami Hiramatsu2010-02-251-61/+67
| | | | | | | | | | | | | | | | | | | | | | | | | Introduce SAVE/RESOTRE_REGS_STRING for cleanup kretprobe-trampoline asm code. These macros will be used for emulating interruption. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133430.6725.83342.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes/x86: Boost probes when reenteringMasami Hiramatsu2010-02-251-22/+26
| | | | | | | | | | | | | | | | | | | | | | | | Integrate prepare_singlestep() into setup_singlestep() to boost up reenter probes, if possible. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133423.6725.12071.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODEMasami Hiramatsu2010-02-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Change RELATIVEJUMP_INSTRUCTION macro to RELATIVEJUMP_OPCODE since it represents just the opcode byte. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133349.6725.99302.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes: Check probe address is reservedMasami Hiramatsu2010-02-041-0/+3
| | | | | | | | | | | | | | | | | | | Check whether the address of new probe is already reserved by ftrace or alternatives (on x86) when registering new probe. If reserved, it returns an error and not register the probe. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: przemyslaw@pawelczyk.it Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Jason Baron <jbaron@redhat.com> LKML-Reference: <20100202214918.4694.94179.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kprobes: Disable booster when CONFIG_PREEMPT=yMasami Hiramatsu2010-02-041-1/+1
| | | | | | | | | | | | | | | | | | | | | Disable kprobe booster when CONFIG_PREEMPT=y at this time, because it can't ensure that all kernel threads preempted on kprobe's boosted slot run out from the slot even using freeze_processes(). The booster on preemptive kernel will be resumed if synchronize_tasks() or something like that is introduced. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20100202214904.4694.24330.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'for-next' into for-linusJiri Kosina2009-12-071-2/+2
|\ | | | | | | | | | | Conflicts: kernel/irq/chip.c
| * tree-wide: fix assorted typos all over the placeAndré Goddard Rosa2009-12-041-2/+2
| | | | | | | | | | | | | | | | | | | | That is "success", "unknown", "through", "performance", "[re|un]mapping" , "access", "default", "reasonable", "[con]currently", "temperature" , "channel", "[un]used", "application", "example","hierarchy", "therefore" , "[over|under]flow", "contiguous", "threshold", "enough" and others. Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | Merge branch 'x86-cleanups-for-linus' of ↵Linus Torvalds2009-12-051-13/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix a section mismatch in arch/x86/kernel/setup.c x86: Fixup last users of irq_chip->typename x86: Remove BKL from apm_32 x86: Remove BKL from microcode x86: use kernel_stack_pointer() in kprobes.c x86: use kernel_stack_pointer() in kgdb.c x86: use kernel_stack_pointer() in dumpstack.c x86: use kernel_stack_pointer() in process_32.c
| * | x86: use kernel_stack_pointer() in kprobes.cH. Peter Anvin2009-10-121-13/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | The way to obtain a kernel-mode stack pointer from a struct pt_regs in 32-bit mode is "subtle": the stack doesn't actually contain the stack pointer, but rather the location where it would have been marks the actual previous stack frame. For clarity, use kernel_stack_pointer() instead of coding this weirdness explicitly. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@redhat.com>
* | Merge branch 'tracing/hw-breakpoints' into perf/coreIngo Molnar2009-11-211-1/+8
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/kprobes.c kernel/trace/Makefile Merge reason: hw-breakpoints perf integration is looking good in testing and in reviews, plus conflicts are mounting up - so merge & resolve. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | hw-breakpoints: reset bits in dr6 after the corresponding exception is handledK.Prasad2009-06-021-1/+8
| |/ | | | | | | | | | | | | | | | | | | | | This patch resets the bit in dr6 after the corresponding exception is handled in code, so that we keep a clean track of the current virtual debug status register. [ Impact: keep track of breakpoints triggering completion ] Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | kprobes/x86-64: Allow to reenter probe on post_handlerMasami Hiramatsu2009-08-301-11/+0
| | | | | | | | | | | | | | | | | | | | | | | | Allow to reenter probe on the post_handler of another probe on x86-64, because x86-64 already allows reentering int3. In that case, reentered probe just increases kp.nmissed and returns. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20090827172304.8246.4822.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | kprobes/x86: Call BUG() when reentering probe into KPROBES_HIT_SSMasami Hiramatsu2009-08-301-16/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Call BUG() when a probe have been hit on the way of kprobe processing path, because that kind of probes are currently unrecoverable (recovering it will cause an infinite loop and stack overflow). The original code seems to assume that it's caused by an int3 which another subsystem inserted on out-of-line singlestep buffer if the hitting probe is same as current probe. However, in that case, int3-hitting-address is on the out-of-line buffer and should be different from first (current) int3 address. Thus, I decided to remove the code. I also removes arch_disarm_kprobe() because it will involve other stuffs in text_poke(). Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20090827172258.8246.61889.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | tracing/kprobes: Dump the culprit kprobe in case of kprobe recursionFrederic Weisbecker2009-08-271-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kprobes can enter into a probing recursion, ie: a kprobe that does an endless loop because one of its core mechanism function used during probing is also probed itself. This patch helps pinpointing the kprobe that raised such recursion by dumping it and raising a BUG instead of a warning (we also disarm the kprobe to try avoiding recursion in BUG itself). Having a BUG instead of a warning stops the stacktrace in the right place and doesn't pollute the logs with hundreds of traces that eventually end up in a stack overflow. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
* | kprobes: Cleanup fix_riprel() using insn decoder on x86Masami Hiramatsu2009-08-271-105/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cleanup fix_riprel() in arch/x86/kernel/kprobes.c by using the new x86 instruction decoder instead of using comparisons with raw ad hoc numeric opcodes. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Avi Kivity <avi@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jason Baron <jbaron@redhat.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it> Cc: Roland McGrath <roland@redhat.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> LKML-Reference: <20090813203436.31965.34374.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | kprobes: Checks probe address is instruction boudary on x86Masami Hiramatsu2009-08-271-0/+73
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ensure safeness of inserting kprobes by checking whether the specified address is at the first byte of an instruction on x86. This is done by decoding probed function from its head to the probe point. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Avi Kivity <avi@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jason Baron <jbaron@redhat.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it> Cc: Roland McGrath <roland@redhat.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> LKML-Reference: <20090813203428.31965.21939.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* Merge branch 'tracing/core-v2' into tracing-for-linusIngo Molnar2009-04-021-8/+9
|\ | | | | | | | | | | | | | | Conflicts: include/linux/slub_def.h lib/Kconfig.debug mm/slob.c mm/slub.c
| * x86: kretprobe-booster interrupt emulation code fixMasami Hiramatsu2009-03-251-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix interrupt emulation code in kretprobe-booster according to pt_regs update (es/ds change and gs adding). This issue has been reported on systemtap-bugzilla: http://sources.redhat.com/bugzilla/show_bug.cgi?id=9965 | On a -tip kernel on x86_32, kretprobe_example (from samples) triggers the | following backtrace when its retprobing a class of functions that cause a | copy_from/to_user(). | | BUG: sleeping function called from invalid context at mm/memory.c:3196 | in_atomic(): 0, irqs_disabled(): 1, pid: 2286, name: cat Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: systemtap-ml <systemtap@sources.redhat.com> LKML-Reference: <49C7995C.2010601@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | x86: kprobes.c fix compilation warningJaswinder Singh Rajput2009-03-181-1/+1
|/ | | | | | | | | | arch/x86/kernel/kprobes.c:196: warning: passing argument 1 of ‘search_exception_tables’ makes integer from pointer without a cast Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference:<49BED952.2050809@redhat.com> LKML-Reference: <1237378065.13488.2.camel@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* prevent boosting kprobes on exception addressMasami Hiramatsu2009-03-171-0/+3
| | | | | | | | | | | | | Don't boost at the addresses which are listed on exception tables, because major page fault will occur on those addresses. In that case, kprobes can not ensure that when instruction buffer can be freed since some processes will sleep on the buffer. kprobes-ia64 already has same check. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kprobes: check CONFIG_FREEZER instead of CONFIG_PMMasami Hiramatsu2009-01-161-1/+1
| | | | | | | | | | | | | | Check CONFIG_FREEZER instead of CONFIG_PM because kprobe booster depends on freeze_processes() and thaw_processes() when CONFIG_PREEMPT=y. This fixes a linkage error which occurs when CONFIG_PREEMPT=y, CONFIG_PM=y and CONFIG_FREEZER=n. Reported-by: Cheng Renquan <crquan@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Len Brown <len.brown@intel.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2009-01-071-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (24 commits) trivial: chack -> check typo fix in main Makefile trivial: Add a space (and a comma) to a printk in 8250 driver trivial: Fix misspelling of "firmware" in docs for ncr53c8xx/sym53c8xx trivial: Fix misspelling of "firmware" in powerpc Makefile trivial: Fix misspelling of "firmware" in usb.c trivial: Fix misspelling of "firmware" in qla1280.c trivial: Fix misspelling of "firmware" in a100u2w.c trivial: Fix misspelling of "firmware" in megaraid.c trivial: Fix misspelling of "firmware" in ql4_mbx.c trivial: Fix misspelling of "firmware" in acpi_memhotplug.c trivial: Fix misspelling of "firmware" in ipw2100.c trivial: Fix misspelling of "firmware" in atmel.c trivial: Fix misspelled firmware in Kconfig trivial: fix an -> a typos in documentation and comments trivial: fix then -> than typos in comments and documentation trivial: update Jesper Juhl CREDITS entry with new email trivial: fix singal -> signal typo trivial: Fix incorrect use of "loose" in event.c trivial: printk: fix indentation of new_text_line declaration trivial: rtc-stk17ta8: fix sparse warning ...
| * trivial: fix then -> than typos in comments and documentationFrederik Schwarzer2009-01-061-1/+1
| | | | | | | | | | | | | | - (better, more, bigger ...) then -> (...) than Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | kprobes: add kprobe_insn_mutex and cleanup arch_remove_kprobe()Masami Hiramatsu2009-01-061-3/+4
|/ | | | | | | | | | | | | | | | | | | | | | Add kprobe_insn_mutex for protecting kprobe_insn_pages hlist, and remove kprobe_mutex from architecture dependent code. This allows us to call arch_remove_kprobe() (and free_insn_slot) while holding kprobe_mutex. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kprobes: improve kretprobe scalability with hashed lockingSrinivasa D S2008-07-251-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently list of kretprobe instances are stored in kretprobe object (as used_instances,free_instances) and in kretprobe hash table. We have one global kretprobe lock to serialise the access to these lists. This causes only one kretprobe handler to execute at a time. Hence affects system performance, particularly on SMP systems and when return probe is set on lot of functions (like on all systemcalls). Solution proposed here gives fine-grain locks that performs better on SMP system compared to present kretprobe implementation. Solution: 1) Instead of having one global lock to protect kretprobe instances present in kretprobe object and kretprobe hash table. We will have two locks, one lock for protecting kretprobe hash table and another lock for kretporbe object. 2) We hold lock present in kretprobe object while we modify kretprobe instance in kretprobe object and we hold per-hash-list lock while modifying kretprobe instances present in that hash list. To prevent deadlock, we never grab a per-hash-list lock while holding a kretprobe lock. 3) We can remove used_instances from struct kretprobe, as we can track used instances of kretprobe instances using kretprobe hash table. Time duration for kernel compilation ("make -j 8") on a 8-way ppc64 system with return probes set on all systemcalls looks like this. cacheline non-cacheline Un-patched kernel aligned patch aligned patch =============================================================================== real 9m46.784s 9m54.412s 10m2.450s user 40m5.715s 40m7.142s 40m4.273s sys 2m57.754s 2m58.583s 3m17.430s =========================================================== Time duration for kernel compilation ("make -j 8) on the same system, when kernel is not probed. ========================= real 9m26.389s user 40m8.775s sys 2m7.283s ========================= Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com> Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Kprobe smoke test lockdep warningPeter Zijlstra2008-07-151-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On Mon, 2008-04-21 at 18:54 -0400, Masami Hiramatsu wrote: > Thank you for reporting. > > Actually, kprobes tries to fixup thread's flags in post_kprobe_handler > (which is called from kprobe_exceptions_notify) by > trace_hardirqs_fixup_flags(pt_regs->flags). However, even the irq flag > is set in pt_regs->flags, true hardirq is still off until returning > from do_debug. Thus, lockdep assumes that hardirq is off without annotation. > > IMHO, one possible solution is that fixing hardirq flags right after > notify_die in do_debug instead of in post_kprobe_handler. My reply to BZ 10489: > [ 2.707509] Kprobe smoke test started > [ 2.709300] ------------[ cut here ]------------ > [ 2.709420] WARNING: at kernel/lockdep.c:2658 check_flags+0x4d/0x12c() > [ 2.709541] Modules linked in: > [ 2.709588] Pid: 1, comm: swapper Not tainted 2.6.25.jml.057 #1 > [ 2.709588] [<c0126acc>] warn_on_slowpath+0x41/0x51 > [ 2.709588] [<c010bafc>] ? save_stack_trace+0x1d/0x3b > [ 2.709588] [<c0140a83>] ? save_trace+0x37/0x89 > [ 2.709588] [<c011987d>] ? kernel_map_pages+0x103/0x11c > [ 2.709588] [<c0109803>] ? native_sched_clock+0xca/0xea > [ 2.709588] [<c0142958>] ? mark_held_locks+0x41/0x5c > [ 2.709588] [<c0382580>] ? kprobe_exceptions_notify+0x322/0x3af > [ 2.709588] [<c0142aff>] ? trace_hardirqs_on+0xf1/0x119 > [ 2.709588] [<c03825b3>] ? kprobe_exceptions_notify+0x355/0x3af > [ 2.709588] [<c0140823>] check_flags+0x4d/0x12c > [ 2.709588] [<c0143c9d>] lock_release+0x58/0x195 > [ 2.709588] [<c038347c>] ? __atomic_notifier_call_chain+0x0/0x80 > [ 2.709588] [<c03834d6>] __atomic_notifier_call_chain+0x5a/0x80 > [ 2.709588] [<c0383508>] atomic_notifier_call_chain+0xc/0xe > [ 2.709588] [<c013b6d4>] notify_die+0x2d/0x2f > [ 2.709588] [<c038168a>] do_debug+0x67/0xfe > [ 2.709588] [<c0381287>] debug_stack_correct+0x27/0x30 > [ 2.709588] [<c01564c0>] ? kprobe_target+0x1/0x34 > [ 2.709588] [<c0156572>] ? init_test_probes+0x50/0x186 > [ 2.709588] [<c04fae48>] init_kprobes+0x85/0x8c > [ 2.709588] [<c04e947b>] kernel_init+0x13d/0x298 > [ 2.709588] [<c04e933e>] ? kernel_init+0x0/0x298 > [ 2.709588] [<c04e933e>] ? kernel_init+0x0/0x298 > [ 2.709588] [<c0105ef7>] kernel_thread_helper+0x7/0x10 > [ 2.709588] ======================= > [ 2.709588] ---[ end trace 778e504de7e3b1e3 ]--- > [ 2.709588] possible reason: unannotated irqs-off. > [ 2.709588] irq event stamp: 370065 > [ 2.709588] hardirqs last enabled at (370065): [<c0382580>] kprobe_exceptions_notify+0x322/0x3af > [ 2.709588] hardirqs last disabled at (370064): [<c0381bb7>] do_int3+0x1d/0x7d > [ 2.709588] softirqs last enabled at (370050): [<c012b464>] __do_softirq+0xfa/0x100 > [ 2.709588] softirqs last disabled at (370045): [<c0107438>] do_softirq+0x74/0xd9 > [ 2.714751] Kprobe smoke test passed successfully how I love this stuff... Ok, do_debug() is a trap, this can happen at any time regardless of the machine's IRQ state. So the first thing we do is fix up the IRQ state. Then we call this die notifier stuff; and return with messed up IRQ state... YAY. So, kprobes fudges it.. notify_die(DIE_DEBUG) kprobe_exceptions_notify() post_kprobe_handler() modify regs->flags trace_hardirqs_fixup_flags(regs->flags); <--- must be it So what's the use of modifying flags if they're not meant to take effect at some point. /me tries to reproduce issue; enable kprobes test thingy && boot OK, that reproduces.. So the below makes it work - but I'm not getting this code; at the time I wrote that stuff I CC'ed each and every kprobe maintainer listed in the usual places but got no reposonse - can some please explain this stuff to me? Are the saved flags only for the TF bit or are they made in full effect later (and if so, where) ? Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: replace most VM86 flags with flags from processor-flags.hgorcunov@gmail.com2008-04-171-1/+1
| | | | | Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, kprobes: correct post-eip value in post_hander()Yakov Lerner2008-04-171-4/+4
| | | | | | | | | | | | | | | | | | | | | I was trying to get the address of instruction to be executed next after the kprobed instruction. But regs->eip in post_handler() contains value which is useless to the user. It's pre-corrected value. This value is difficult to use without access to resume_execution(), which is not exported anyway. I moved the invocation of post_handler() to *after* resume_execution(). Now regs->eip contains meaningful value in post_handler(). I do not think this change breaks any backward-compatibility. To make meaning of the old value, post_handler() would need access to resume_execution() which is not exported. I have difficulty to believe that previous, uncorrected, regs->eip can be meaningfully used in post_handler(). Signed-off-by: Yakov Lerner <iler.ml@gmail.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: prevent unconditional writes to DebugCtl MSRJan Beulich2008-04-171-2/+2
| | | | | | | | | | | | | | Otherwise, enabling (or better, subsequent disabling) of single stepping would cause a kernel oops on CPUs not having this MSR. The patch could have been added a conditional to the MSR write in user_disable_single_step(), but centralizing the updates seems safer and (looking forward) better manageable. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, kprobes: remove sparse warnings from x86Harvey Harrison2008-02-191-2/+2
| | | | | | | | | | | | | | | | | | | arch/x86/kernel/kprobes.c:584:16: warning: symbol 'kretprobe_trampoline_holder' was not declared. Should it be static? arch/x86/kernel/kprobes.c:676:6: warning: symbol 'trampoline_handler' was not declared. Should it be static? Make them static and add the __used attribute, approach taken from the arm kprobes implementation. kretprobe_trampoline_holder uses inline assemly to define the global symbol kretprobe_trampoline, but nothing ever calls the holder explicitly. trampoline handler is only called from inline assembly in the same file, mark it used and static. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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