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Date: Thu, 29 Sep 2022 16:53:09 +0800
From: kernel test robot <lkp@...el.com>
To: Nick Desaulniers <ndesaulniers@...gle.com>,
Russell King <rmk+kernel@...linux.org.uk>,
Masami Hiramatsu <mhiramat@...nel.org>
Cc: kbuild-all@...ts.01.org,
"Naveen N . Rao" <naveen.n.rao@...ux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
"David S . Miller" <davem@...emloft.net>,
Arnd Bergmann <arnd@...db.de>,
Nathan Chancellor <nathan@...nel.org>,
Tom Rix <trix@...hat.com>,
sparkhuang <huangshaobo6@...wei.com>,
Ard Biesheuvel <ardb@...nel.org>,
Steven Rostedt <rostedt@...dmis.org>,
Linus Walleij <linus.walleij@...aro.org>,
Chen Zhongjin <chenzhongjin@...wei.com>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-arch@...r.kernel.org, llvm@...ts.linux.dev,
Naresh Kamboju <naresh.kamboju@...aro.org>,
regressions@...ts.linux.dev, lkft-triage@...ts.linaro.org,
Nick Desaulniers <ndesaulniers@...gle.com>,
Linux Kernel Functional Testing <lkft@...aro.org>,
Logan Chien <loganchien@...gle.com>
Subject: Re: [PATCH] ARM: kprobes: move __kretprobe_trampoline to out of line
assembler
Hi Nick,
I love your patch! Perhaps something to improve:
[auto build test WARNING on next-20220923]
[cannot apply to arm/for-next rostedt-trace/for-next linus/master v6.0-rc7 v6.0-rc6 v6.0-rc5 v6.0-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Nick-Desaulniers/ARM-kprobes-move-__kretprobe_trampoline-to-out-of-line-assembler/20220927-094627
base: aaa11ce2ffc84166d11c4d2ac88c3fcf75425fbd
config: arm-allyesconfig
compiler: arm-linux-gnueabi-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/4dd7f6ce622448f06b7fd5edd8620235c76152aa
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Nick-Desaulniers/ARM-kprobes-move-__kretprobe_trampoline-to-out-of-line-assembler/20220927-094627
git checkout 4dd7f6ce622448f06b7fd5edd8620235c76152aa
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash arch/arm/probes/kprobes/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@...el.com>
Note: functions only called from assembly code should be annotated with the asmlinkage attribute
All warnings (new ones prefixed by >>):
arch/arm/probes/kprobes/core.c:246:16: warning: no previous prototype for 'kprobe_handler' [-Wmissing-prototypes]
246 | void __kprobes kprobe_handler(struct pt_regs *regs)
| ^~~~~~~~~~~~~~
>> arch/arm/probes/kprobes/core.c:381:17: warning: no previous prototype for 'trampoline_handler' [-Wmissing-prototypes]
381 | __kprobes void *trampoline_handler(struct pt_regs *regs)
| ^~~~~~~~~~~~~~~~~~
vim +/trampoline_handler +381 arch/arm/probes/kprobes/core.c
238
239 /*
240 * Called with IRQs disabled. IRQs must remain disabled from that point
241 * all the way until processing this kprobe is complete. The current
242 * kprobes implementation cannot process more than one nested level of
243 * kprobe, and that level is reserved for user kprobe handlers, so we can't
244 * risk encountering a new kprobe in an interrupt handler.
245 */
> 246 void __kprobes kprobe_handler(struct pt_regs *regs)
247 {
248 struct kprobe *p, *cur;
249 struct kprobe_ctlblk *kcb;
250
251 kcb = get_kprobe_ctlblk();
252 cur = kprobe_running();
253
254 #ifdef CONFIG_THUMB2_KERNEL
255 /*
256 * First look for a probe which was registered using an address with
257 * bit 0 set, this is the usual situation for pointers to Thumb code.
258 * If not found, fallback to looking for one with bit 0 clear.
259 */
260 p = get_kprobe((kprobe_opcode_t *)(regs->ARM_pc | 1));
261 if (!p)
262 p = get_kprobe((kprobe_opcode_t *)regs->ARM_pc);
263
264 #else /* ! CONFIG_THUMB2_KERNEL */
265 p = get_kprobe((kprobe_opcode_t *)regs->ARM_pc);
266 #endif
267
268 if (p) {
269 if (!p->ainsn.insn_check_cc(regs->ARM_cpsr)) {
270 /*
271 * Probe hit but conditional execution check failed,
272 * so just skip the instruction and continue as if
273 * nothing had happened.
274 * In this case, we can skip recursing check too.
275 */
276 singlestep_skip(p, regs);
277 } else if (cur) {
278 /* Kprobe is pending, so we're recursing. */
279 switch (kcb->kprobe_status) {
280 case KPROBE_HIT_ACTIVE:
281 case KPROBE_HIT_SSDONE:
282 case KPROBE_HIT_SS:
283 /* A pre- or post-handler probe got us here. */
284 kprobes_inc_nmissed_count(p);
285 save_previous_kprobe(kcb);
286 set_current_kprobe(p);
287 kcb->kprobe_status = KPROBE_REENTER;
288 singlestep(p, regs, kcb);
289 restore_previous_kprobe(kcb);
290 break;
291 case KPROBE_REENTER:
292 /* A nested probe was hit in FIQ, it is a BUG */
293 pr_warn("Failed to recover from reentered kprobes.\n");
294 dump_kprobe(p);
295 fallthrough;
296 default:
297 /* impossible cases */
298 BUG();
299 }
300 } else {
301 /* Probe hit and conditional execution check ok. */
302 set_current_kprobe(p);
303 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
304
305 /*
306 * If we have no pre-handler or it returned 0, we
307 * continue with normal processing. If we have a
308 * pre-handler and it returned non-zero, it will
309 * modify the execution path and no need to single
310 * stepping. Let's just reset current kprobe and exit.
311 */
312 if (!p->pre_handler || !p->pre_handler(p, regs)) {
313 kcb->kprobe_status = KPROBE_HIT_SS;
314 singlestep(p, regs, kcb);
315 if (p->post_handler) {
316 kcb->kprobe_status = KPROBE_HIT_SSDONE;
317 p->post_handler(p, regs, 0);
318 }
319 }
320 reset_current_kprobe();
321 }
322 } else {
323 /*
324 * The probe was removed and a race is in progress.
325 * There is nothing we can do about it. Let's restart
326 * the instruction. By the time we can restart, the
327 * real instruction will be there.
328 */
329 }
330 }
331
332 static int __kprobes kprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
333 {
334 unsigned long flags;
335 local_irq_save(flags);
336 kprobe_handler(regs);
337 local_irq_restore(flags);
338 return 0;
339 }
340
341 int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr)
342 {
343 struct kprobe *cur = kprobe_running();
344 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
345
346 switch (kcb->kprobe_status) {
347 case KPROBE_HIT_SS:
348 case KPROBE_REENTER:
349 /*
350 * We are here because the instruction being single
351 * stepped caused a page fault. We reset the current
352 * kprobe and the PC to point back to the probe address
353 * and allow the page fault handler to continue as a
354 * normal page fault.
355 */
356 regs->ARM_pc = (long)cur->addr;
357 if (kcb->kprobe_status == KPROBE_REENTER) {
358 restore_previous_kprobe(kcb);
359 } else {
360 reset_current_kprobe();
361 }
362 break;
363 }
364
365 return 0;
366 }
367
368 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
369 unsigned long val, void *data)
370 {
371 /*
372 * notify_die() is currently never called on ARM,
373 * so this callback is currently empty.
374 */
375 return NOTIFY_DONE;
376 }
377
378 /*void __kretprobe_trampoline(void);*/
379
380 /* Called from __kretprobe_trampoline */
> 381 __kprobes void *trampoline_handler(struct pt_regs *regs)
382 {
383 return (void *)kretprobe_trampoline_handler(regs, (void *)regs->TRAMP_FP);
384 }
385
--
0-DAY CI Kernel Test Service
https://01.org/lkp
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