arch/arc/kernel/smp.c:279:18: sparse: sparse: dereference of noderef expression
From: kernel test robot
Date: Sun Jul 31 2022 - 04:02:05 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 6a010258447d386186ca10cd374d888ac66ffe1a
commit: e188f3330a13df904d77003846eafd3edf99009d ARC: cmpxchg/xchg: rewrite as macros to make type safe
date: 11 months ago
config: arc-randconfig-s033-20220730 (https://download.01.org/0day-ci/archive/20220731/202207311543.rtDsgvTj-lkp@xxxxxxxxx/config)
compiler: arc-elf-gcc (GCC) 12.1.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.4-39-gce1a6720-dirty
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e188f3330a13df904d77003846eafd3edf99009d
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout e188f3330a13df904d77003846eafd3edf99009d
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=arc SHELL=/bin/bash arch/arc/kernel/ drivers/vfio/ kernel/debug/kdb/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>
sparse warnings: (new ones prefixed by >>)
arch/arc/kernel/smp.c:264:48: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected unsigned long [noderef] __percpu *ipi_data_ptr @@ got unsigned long * @@
arch/arc/kernel/smp.c:264:48: sparse: expected unsigned long [noderef] __percpu *ipi_data_ptr
arch/arc/kernel/smp.c:264:48: sparse: got unsigned long *
arch/arc/kernel/smp.c:279:18: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void const volatile *v @@ got unsigned long [noderef] __percpu *__ai_ptr @@
arch/arc/kernel/smp.c:279:18: sparse: expected void const volatile *v
arch/arc/kernel/smp.c:279:18: sparse: got unsigned long [noderef] __percpu *__ai_ptr
arch/arc/kernel/smp.c:277:29: sparse: sparse: cast removes address space '__percpu' of expression
arch/arc/kernel/smp.c:413:72: sparse: sparse: incorrect type in argument 4 (different address spaces) @@ expected void [noderef] __percpu *percpu_dev_id @@ got int *dev @@
arch/arc/kernel/smp.c:413:72: sparse: expected void [noderef] __percpu *percpu_dev_id
arch/arc/kernel/smp.c:413:72: sparse: got int *dev
>> arch/arc/kernel/smp.c:279:18: sparse: sparse: dereference of noderef expression
>> arch/arc/kernel/smp.c:279:18: sparse: sparse: dereference of noderef expression
vim +279 arch/arc/kernel/smp.c
41195d236e8445 Vineet Gupta 2013-01-18 261
ddf84433f411b6 Vineet Gupta 2013-11-25 262 static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
41195d236e8445 Vineet Gupta 2013-01-18 263 {
f2a4aa5646687f Vineet Gupta 2013-11-26 264 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);
d8e8c7dda11f5d Vineet Gupta 2013-11-28 265 unsigned long old, new;
41195d236e8445 Vineet Gupta 2013-01-18 266 unsigned long flags;
41195d236e8445 Vineet Gupta 2013-01-18 267
f2a4aa5646687f Vineet Gupta 2013-11-26 268 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);
f2a4aa5646687f Vineet Gupta 2013-11-26 269
41195d236e8445 Vineet Gupta 2013-01-18 270 local_irq_save(flags);
41195d236e8445 Vineet Gupta 2013-01-18 271
d8e8c7dda11f5d Vineet Gupta 2013-11-28 272 /*
d8e8c7dda11f5d Vineet Gupta 2013-11-28 273 * Atomically write new msg bit (in case others are writing too),
d8e8c7dda11f5d Vineet Gupta 2013-11-28 274 * and read back old value
d8e8c7dda11f5d Vineet Gupta 2013-11-28 275 */
d8e8c7dda11f5d Vineet Gupta 2013-11-28 276 do {
6aa7de059173a9 Mark Rutland 2017-10-23 277 new = old = READ_ONCE(*ipi_data_ptr);
d8e8c7dda11f5d Vineet Gupta 2013-11-28 278 new |= 1U << msg;
d8e8c7dda11f5d Vineet Gupta 2013-11-28 @279 } while (cmpxchg(ipi_data_ptr, old, new) != old);
41195d236e8445 Vineet Gupta 2013-01-18 280
d8e8c7dda11f5d Vineet Gupta 2013-11-28 281 /*
d8e8c7dda11f5d Vineet Gupta 2013-11-28 282 * Call the platform specific IPI kick function, but avoid if possible:
d8e8c7dda11f5d Vineet Gupta 2013-11-28 283 * Only do so if there's no pending msg from other concurrent sender(s).
82a423053eb3cf Changcheng Deng 2021-08-14 284 * Otherwise, receiver will see this msg as well when it takes the
d8e8c7dda11f5d Vineet Gupta 2013-11-28 285 * IPI corresponding to that msg. This is true, even if it is already in
d8e8c7dda11f5d Vineet Gupta 2013-11-28 286 * IPI handler, because !@old means it has not yet dequeued the msg(s)
d8e8c7dda11f5d Vineet Gupta 2013-11-28 287 * so @new msg can be a free-loader
d8e8c7dda11f5d Vineet Gupta 2013-11-28 288 */
d8e8c7dda11f5d Vineet Gupta 2013-11-28 289 if (plat_smp_ops.ipi_send && !old)
ddf84433f411b6 Vineet Gupta 2013-11-25 290 plat_smp_ops.ipi_send(cpu);
41195d236e8445 Vineet Gupta 2013-01-18 291
41195d236e8445 Vineet Gupta 2013-01-18 292 local_irq_restore(flags);
41195d236e8445 Vineet Gupta 2013-01-18 293 }
41195d236e8445 Vineet Gupta 2013-01-18 294
:::::: The code at line 279 was first introduced by commit
:::::: d8e8c7dda11f5d5cf90495f2e89d917a83509bc0 ARC: [SMP] optimize IPI send and receive
:::::: TO: Vineet Gupta <vgupta@xxxxxxxxxxxx>
:::::: CC: Vineet Gupta <vgupta@xxxxxxxxxxxx>
--
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