From: kernel test robot <lkp@intel.com>
To: Song Liu <song@kernel.org>
Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
Mike Rapoport <rppt@kernel.org>
Subject: [rppt:perm_alloc/v0 9/13] arch/x86/kernel/ftrace.c:418:44: warning: variable 'npages' is uninitialized when used here
Date: Thu, 1 Jun 2023 02:41:58 +0800 [thread overview]
Message-ID: <202306010220.wZPmbp7W-lkp@intel.com> (raw)
tree: https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git perm_alloc/v0
head: a92ef5aa5306aeaadefc1625e1a48c6832aa0a26
commit: b99e562f2ff2ff567b283d6502986246ab698544 [9/13] x86: prepare to allocate exectuatble memory as ROX
config: x86_64-randconfig-a011-20230531 (https://download.01.org/0day-ci/archive/20230601/202306010220.wZPmbp7W-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
mkdir -p ~/bin
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/commit/?id=b99e562f2ff2ff567b283d6502986246ab698544
git remote add rppt https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git
git fetch --no-tags rppt perm_alloc/v0
git checkout b99e562f2ff2ff567b283d6502986246ab698544
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/kernel/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306010220.wZPmbp7W-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> arch/x86/kernel/ftrace.c:418:44: warning: variable 'npages' is uninitialized when used here [-Wuninitialized]
set_memory_rox((unsigned long)trampoline, npages);
^~~~~~
arch/x86/kernel/ftrace.c:316:22: note: initialize the variable 'npages' to silence this warning
unsigned long npages;
^
= 0
1 warning generated.
vim +/npages +418 arch/x86/kernel/ftrace.c
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 306)
aec0be2d6e9f02 Steven Rostedt (Red Hat 2014-11-18 307) static unsigned long
aec0be2d6e9f02 Steven Rostedt (Red Hat 2014-11-18 308) create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 309) {
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 310) unsigned long start_offset;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 311) unsigned long end_offset;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 312) unsigned long op_offset;
768ae4406a5cab Peter Zijlstra 2019-08-26 313 unsigned long call_offset;
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 314) unsigned long jmp_offset;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 315) unsigned long offset;
3c0dab44e22782 Nadav Amit 2019-04-25 316 unsigned long npages;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 317) unsigned long size;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 318) unsigned long *ptr;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 319) void *trampoline;
ee3e2469b3463d Peter Zijlstra 2022-09-15 320 void *ip, *dest;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 321) /* 48 8b 15 <offset> is movq <offset>(%rip), %rdx */
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 322) unsigned const char op_ref[] = { 0x48, 0x8b, 0x15 };
e52fc2cf3f6628 Peter Zijlstra 2022-03-08 323 unsigned const char retq[] = { RET_INSN_OPCODE, INT3_INSN_OPCODE };
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 324) union ftrace_op_code_union op_ptr;
b99e562f2ff2ff Song Liu 2023-05-25 325 void *ret;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 326)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 327) if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 328) start_offset = (unsigned long)ftrace_regs_caller;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 329) end_offset = (unsigned long)ftrace_regs_caller_end;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 330) op_offset = (unsigned long)ftrace_regs_caller_op_ptr;
768ae4406a5cab Peter Zijlstra 2019-08-26 331 call_offset = (unsigned long)ftrace_regs_call;
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 332) jmp_offset = (unsigned long)ftrace_regs_caller_jmp;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 333) } else {
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 334) start_offset = (unsigned long)ftrace_caller;
0298739b7983cf Peter Zijlstra 2020-04-01 335 end_offset = (unsigned long)ftrace_caller_end;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 336) op_offset = (unsigned long)ftrace_caller_op_ptr;
768ae4406a5cab Peter Zijlstra 2019-08-26 337 call_offset = (unsigned long)ftrace_call;
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 338) jmp_offset = 0;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 339) }
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 340)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 341) size = end_offset - start_offset;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 342)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 343) /*
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 344) * Allocate enough size to store the ftrace_caller code,
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 345) * the iret , as well as the address of the ftrace_ops this
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 346) * trampoline is used for.
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 347) */
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 348) trampoline = alloc_tramp(size + RET_SIZE + sizeof(void *));
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 349) if (!trampoline)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 350) return 0;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 351)
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 352) *tramp_size = size + RET_SIZE + sizeof(void *);
aec0be2d6e9f02 Steven Rostedt (Red Hat 2014-11-18 353)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 354) /* Copy ftrace_caller onto the trampoline memory */
b99e562f2ff2ff Song Liu 2023-05-25 355 ret = text_poke_copy(trampoline, (void *)start_offset, size);
b99e562f2ff2ff Song Liu 2023-05-25 356 if (WARN_ON(!ret))
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 357) goto fail;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 358)
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 359) ip = trampoline + size;
1f001e9da6bbf4 Peter Zijlstra 2022-06-14 360 if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
770ae1b709528a Peter Zijlstra 2022-09-15 361 __text_gen_insn(ip, JMP32_INSN_OPCODE, ip, x86_return_thunk, JMP32_INSN_SIZE);
1f001e9da6bbf4 Peter Zijlstra 2022-06-14 362 else
b99e562f2ff2ff Song Liu 2023-05-25 363 text_poke_copy(ip, retq, sizeof(retq));
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 364)
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 365) /* No need to test direct calls on created trampolines */
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 366) if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 367) /* NOP the jnz 1f; but make sure it's a 2 byte jnz */
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 368) ip = trampoline + (jmp_offset - start_offset);
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 369) if (WARN_ON(*(char *)ip != 0x75))
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 370) goto fail;
b99e562f2ff2ff Song Liu 2023-05-25 371 if (!text_poke_copy(ip, x86_nops[2], 2))
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 372) goto fail;
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 373) }
fe58acefd5a66d Steven Rostedt (VMware 2020-04-22 374)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 375) /*
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 376) * The address of the ftrace_ops that is used for this trampoline
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 377) * is stored at the end of the trampoline. This will be used to
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 378) * load the third parameter for the callback. Basically, that
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 379) * location at the end of the trampoline takes the place of
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 380) * the global function_trace_op variable.
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 381) */
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 382)
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 383) ptr = (unsigned long *)(trampoline + size + RET_SIZE);
b99e562f2ff2ff Song Liu 2023-05-25 384 text_poke_copy(ptr, &ops, sizeof(unsigned long));
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 385)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 386) op_offset -= start_offset;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 387) memcpy(&op_ptr, trampoline + op_offset, OP_REF_SIZE);
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 388)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 389) /* Are we pointing to the reference? */
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 390) if (WARN_ON(memcmp(op_ptr.op, op_ref, 3) != 0))
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 391) goto fail;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 392)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 393) /* Load the contents of ptr into the callback parameter */
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 394) offset = (unsigned long)ptr;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 395) offset -= (unsigned long)trampoline + op_offset + OP_REF_SIZE;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 396)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 397) op_ptr.offset = offset;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 398)
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 399) /* put in the new offset to the ftrace_ops */
b99e562f2ff2ff Song Liu 2023-05-25 400 text_poke_copy(trampoline + op_offset, &op_ptr, OP_REF_SIZE);
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 401)
768ae4406a5cab Peter Zijlstra 2019-08-26 402 /* put in the call to the function */
768ae4406a5cab Peter Zijlstra 2019-08-26 403 mutex_lock(&text_mutex);
768ae4406a5cab Peter Zijlstra 2019-08-26 404 call_offset -= start_offset;
ee3e2469b3463d Peter Zijlstra 2022-09-15 405 /*
ee3e2469b3463d Peter Zijlstra 2022-09-15 406 * No need to translate into a callthunk. The trampoline does
ee3e2469b3463d Peter Zijlstra 2022-09-15 407 * the depth accounting before the call already.
ee3e2469b3463d Peter Zijlstra 2022-09-15 408 */
ee3e2469b3463d Peter Zijlstra 2022-09-15 409 dest = ftrace_ops_get_func(ops);
b99e562f2ff2ff Song Liu 2023-05-25 410 text_poke_copy_locked(trampoline + call_offset,
ee3e2469b3463d Peter Zijlstra 2022-09-15 411 text_gen_insn(CALL_INSN_OPCODE, trampoline + call_offset, dest),
b99e562f2ff2ff Song Liu 2023-05-25 412 CALL_INSN_SIZE, false);
768ae4406a5cab Peter Zijlstra 2019-08-26 413 mutex_unlock(&text_mutex);
768ae4406a5cab Peter Zijlstra 2019-08-26 414
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 415) /* ALLOC_TRAMP flags lets us know we created it */
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 416) ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 417)
d48567c9a0d1e6 Peter Zijlstra 2022-10-26 @418 set_memory_rox((unsigned long)trampoline, npages);
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 419) return (unsigned long)trampoline;
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 420) fail:
7fdfe1e40b225b Rick Edgecombe 2019-04-25 421 tramp_free(trampoline);
d2a68c4effd821 Steven Rostedt (VMware 2018-12-08 422) return 0;
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 423) }
f3bea49115b21e Steven Rostedt (Red Hat 2014-07-02 424)
:::::: The code at line 418 was first introduced by commit
:::::: d48567c9a0d1e605639f8a8705a61bbb55fb4e84 mm: Introduce set_memory_rox()
:::::: TO: Peter Zijlstra <peterz@infradead.org>
:::::: CC: Dave Hansen <dave.hansen@linux.intel.com>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
reply other threads:[~2023-05-31 18:42 UTC|newest]
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