Re: [PATCH v5 09/12] user_events: Optimize writing events by only copying data once
From: kernel test robot
Date: Sat Nov 27 2021 - 10:12:25 EST
Hi Beau,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on 67d4f6e3bf5dddced226fbf19704cdbbb0c98847]
url: https://github.com/0day-ci/linux/commits/Beau-Belgrave/user_events-Enable-user-processes-to-create-and-write-to-trace-events/20211116-090533
base: 67d4f6e3bf5dddced226fbf19704cdbbb0c98847
config: hexagon-randconfig-r031-20211116 (https://download.01.org/0day-ci/archive/20211127/202111272346.r2ZhQ5KM-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project fbe72e41b99dc7994daac300d208a955be3e4a0a)
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/0day-ci/linux/commit/5d08d02e133130c59d164c17756a0aa0abb5418c
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Beau-Belgrave/user_events-Enable-user-processes-to-create-and-write-to-trace-events/20211116-090533
git checkout 5d08d02e133130c59d164c17756a0aa0abb5418c
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/gpio/ kernel/trace/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
All warnings (new ones prefixed by >>):
>> kernel/trace/trace_events_user.c:563:22: warning: comparison of distinct pointer types ('typeof (i->count) *' (aka 'unsigned int *') and 'typeof ((1UL << 16)) *' (aka 'unsigned long *')) [-Wcompare-distinct-pointer-types]
size_t copy_size = min(i->count, MAX_BPF_COPY_SIZE);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/minmax.h:45:19: note: expanded from macro 'min'
#define min(x, y) __careful_cmp(x, y, <)
^~~~~~~~~~~~~~~~~~~~~~
include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
__builtin_choose_expr(__safe_cmp(x, y), \
^~~~~~~~~~~~~~~~
include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
(__typecheck(x, y) && __no_side_effects(x, y))
^~~~~~~~~~~~~~~~~
include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
1 warning generated.
vim +563 kernel/trace/trace_events_user.c
537
538 #ifdef CONFIG_PERF_EVENTS
539 static void user_event_bpf(struct user_event *user, struct iov_iter *i)
540 {
541 struct user_bpf_context context;
542 struct user_bpf_iter bpf_i;
543 char fast_data[MAX_STACK_BPF_DATA];
544 void *temp = NULL;
545
546 if ((user->flags & FLAG_BPF_ITER) && iter_is_iovec(i)) {
547 /* Raw iterator */
548 context.data_type = USER_BPF_DATA_ITER;
549 context.data_len = i->count;
550 context.iter = &bpf_i;
551
552 bpf_i.iov_offset = i->iov_offset;
553 bpf_i.iov = i->iov;
554 bpf_i.nr_segs = i->nr_segs;
555 } else if (i->nr_segs == 1 && iter_is_iovec(i)) {
556 /* Single buffer from user */
557 context.data_type = USER_BPF_DATA_USER;
558 context.data_len = i->count;
559 context.udata = i->iov->iov_base + i->iov_offset;
560 } else {
561 /* Multi buffer from user */
562 struct iov_iter copy = *i;
> 563 size_t copy_size = min(i->count, MAX_BPF_COPY_SIZE);
564
565 context.data_type = USER_BPF_DATA_KERNEL;
566 context.kdata = fast_data;
567
568 if (unlikely(copy_size > sizeof(fast_data))) {
569 temp = kmalloc(copy_size, GFP_NOWAIT);
570
571 if (temp)
572 context.kdata = temp;
573 else
574 copy_size = sizeof(fast_data);
575 }
576
577 context.data_len = copy_nofault(context.kdata,
578 copy_size, ©);
579 }
580
581 trace_call_bpf(&user->call, &context);
582
583 kfree(temp);
584 }
585
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0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx