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Message-ID: <202212171240.YQeGtMVy-lkp@intel.com>
Date: Sat, 17 Dec 2022 12:10:04 +0800
From: kernel test robot <lkp@...el.com>
To: Baoquan He <bhe@...hat.com>, linux-kernel@...r.kernel.org
Cc: llvm@...ts.linux.dev, oe-kbuild-all@...ts.linux.dev,
linux-mm@...ck.org, urezki@...il.com, stephen.s.brennan@...cle.com,
willy@...radead.org, akpm@...ux-foundation.org, hch@...radead.org,
Baoquan He <bhe@...hat.com>
Subject: Re: [PATCH v2 3/7] mm/vmalloc.c: allow vread() to read out
vm_map_ram areas
Hi Baoquan,
I love your patch! Perhaps something to improve:
[auto build test WARNING on akpm-mm/mm-everything]
url: https://github.com/intel-lab-lkp/linux/commits/Baoquan-He/mm-vmalloc-c-allow-vread-to-read-out-vm_map_ram-areas/20221217-095615
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20221217015435.73889-4-bhe%40redhat.com
patch subject: [PATCH v2 3/7] mm/vmalloc.c: allow vread() to read out vm_map_ram areas
config: powerpc-randconfig-r031-20221216
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 98b13979fb05f3ed288a900deb843e7b27589e58)
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
# install powerpc cross compiling tool for clang build
# apt-get install binutils-powerpc-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/368cd65be8fedd1642e53393dc3f28ff8726122d
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Baoquan-He/mm-vmalloc-c-allow-vread-to-read-out-vm_map_ram-areas/20221217-095615
git checkout 368cd65be8fedd1642e53393dc3f28ff8726122d
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@...el.com>
All warnings (new ones prefixed by >>):
>> mm/vmalloc.c:3563:35: warning: operator '<<' has lower precedence than '-'; '-' will be evaluated first [-Wshift-op-parentheses]
n = (re - rs + 1) << PAGE_SHIFT - offset;
~~ ~~~~~~~~~~~^~~~~~~~
mm/vmalloc.c:3563:35: note: place parentheses around the '-' expression to silence this warning
n = (re - rs + 1) << PAGE_SHIFT - offset;
~~~~~~~~~~~^~~~~~~~
1 warning generated.
vim +3563 mm/vmalloc.c
3533
3534 static void vb_vread(char *buf, char *addr, int count)
3535 {
3536 char *start;
3537 struct vmap_block *vb;
3538 unsigned long offset;
3539 unsigned int rs, re, n;
3540
3541 vb = xa_load(&vmap_blocks, addr_to_vb_idx((unsigned long)addr));
3542
3543 spin_lock(&vb->lock);
3544 if (bitmap_empty(vb->used_map, VMAP_BBMAP_BITS)) {
3545 spin_unlock(&vb->lock);
3546 memset(buf, 0, count);
3547 return;
3548 }
3549 for_each_set_bitrange(rs, re, vb->used_map, VMAP_BBMAP_BITS) {
3550 if (!count)
3551 break;
3552 start = vmap_block_vaddr(vb->va->va_start, rs);
3553 if (addr < start) {
3554 if (count == 0)
3555 break;
3556 *buf = '\0';
3557 buf++;
3558 addr++;
3559 count--;
3560 }
3561 /*it could start reading from the middle of used region*/
3562 offset = offset_in_page(addr);
> 3563 n = (re - rs + 1) << PAGE_SHIFT - offset;
3564 if (n > count)
3565 n = count;
3566 aligned_vread(buf, start+offset, n);
3567
3568 buf += n;
3569 addr += n;
3570 count -= n;
3571 }
3572 spin_unlock(&vb->lock);
3573
3574 /* zero-fill the left dirty or free regions */
3575 if (count)
3576 memset(buf, 0, count);
3577 }
3578
--
0-DAY CI Kernel Test Service
https://01.org/lkp
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