| Message ID | 20211213123737.9147-2-wander@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fix warnings in blktrace | expand |
Hi Wander,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on axboe-block/for-next]
[also build test ERROR on linux/master linus/master v5.16-rc5]
[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]
url: https://github.com/0day-ci/linux/commits/Wander-Lairson-Costa/Fix-warnings-in-blktrace/20211213-204207
base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: x86_64-rhel-8.3-kselftests (https://download.01.org/0day-ci/archive/20211214/202112141554.2175ujH7-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
# https://github.com/0day-ci/linux/commit/e53f7f8c1ce0b19fef6164247fea08d17d5f771d
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Wander-Lairson-Costa/Fix-warnings-in-blktrace/20211213-204207
git checkout e53f7f8c1ce0b19fef6164247fea08d17d5f771d
# save the config file to linux build tree
mkdir build_dir
make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
block/blk-cgroup.c: In function 'blk_cgroup_bio_start':
>> block/blk-cgroup.c:1915:8: error: implicit declaration of function 'get_cpu_light'; did you mean 'em_cpu_get'? [-Werror=implicit-function-declaration]
1915 | cpu = get_cpu_light();
| ^~~~~~~~~~~~~
| em_cpu_get
>> block/blk-cgroup.c:1932:2: error: implicit declaration of function 'put_cpu_light'; did you mean 'fput_light'? [-Werror=implicit-function-declaration]
1932 | put_cpu_light();
| ^~~~~~~~~~~~~
| fput_light
cc1: some warnings being treated as errors
vim +1915 block/blk-cgroup.c
1908
1909 void blk_cgroup_bio_start(struct bio *bio)
1910 {
1911 int rwd = blk_cgroup_io_type(bio), cpu;
1912 struct blkg_iostat_set *bis;
1913 unsigned long flags;
1914
> 1915 cpu = get_cpu_light();
1916 bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu);
1917 flags = u64_stats_update_begin_irqsave(&bis->sync);
1918
1919 /*
1920 * If the bio is flagged with BIO_CGROUP_ACCT it means this is a split
1921 * bio and we would have already accounted for the size of the bio.
1922 */
1923 if (!bio_flagged(bio, BIO_CGROUP_ACCT)) {
1924 bio_set_flag(bio, BIO_CGROUP_ACCT);
1925 bis->cur.bytes[rwd] += bio->bi_iter.bi_size;
1926 }
1927 bis->cur.ios[rwd]++;
1928
1929 u64_stats_update_end_irqrestore(&bis->sync, flags);
1930 if (cgroup_subsys_on_dfl(io_cgrp_subsys))
1931 cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu);
> 1932 put_cpu_light();
1933 }
1934
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
On 2021-12-13 09:37:36 [-0300], Wander Lairson Costa wrote: > --- > block/blk-cgroup.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c > index 663aabfeba18..0a532bb3003c 100644 > --- a/block/blk-cgroup.c > +++ b/block/blk-cgroup.c > @@ -1911,7 +1911,7 @@ void blk_cgroup_bio_start(struct bio *bio) > struct blkg_iostat_set *bis; > unsigned long flags; > > - cpu = get_cpu(); > + cpu = get_cpu_light(); > bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu); > flags = u64_stats_update_begin_irqsave(&bis->sync); > > @@ -1928,7 +1928,7 @@ void blk_cgroup_bio_start(struct bio *bio) > u64_stats_update_end_irqrestore(&bis->sync, flags); > if (cgroup_subsys_on_dfl(io_cgrp_subsys)) > cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu); > - put_cpu(); > + put_cpu_light(); > } Are you sure patch and backtrace match? There is also u64_stats_update_begin_irqsave() which disables preemption on RT. So by doing what you are suggesting, you only avoid disabling preemption in cgroup_rstat_updated() which acquires a raw_spinlock_t. Sebastian
On Wed, Dec 15, 2021 at 1:58 PM Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote: > > On 2021-12-13 09:37:36 [-0300], Wander Lairson Costa wrote: > > --- > > block/blk-cgroup.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c > > index 663aabfeba18..0a532bb3003c 100644 > > --- a/block/blk-cgroup.c > > +++ b/block/blk-cgroup.c > > @@ -1911,7 +1911,7 @@ void blk_cgroup_bio_start(struct bio *bio) > > struct blkg_iostat_set *bis; > > unsigned long flags; > > > > - cpu = get_cpu(); > > + cpu = get_cpu_light(); > > bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu); > > flags = u64_stats_update_begin_irqsave(&bis->sync); > > > > @@ -1928,7 +1928,7 @@ void blk_cgroup_bio_start(struct bio *bio) > > u64_stats_update_end_irqrestore(&bis->sync, flags); > > if (cgroup_subsys_on_dfl(io_cgrp_subsys)) > > cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu); > > - put_cpu(); > > + put_cpu_light(); > > } > > Are you sure patch and backtrace match? There is also > u64_stats_update_begin_irqsave() which disables preemption on RT. So by > doing what you are suggesting, you only avoid disabling preemption in > cgroup_rstat_updated() which acquires a raw_spinlock_t. > You're right. I double-checked and noticed my tree didn't have the call to u64_stats_update_begin_irqsave. Only patch 2 is necessary indeed. > Sebastian >
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 663aabfeba18..0a532bb3003c 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1911,7 +1911,7 @@ void blk_cgroup_bio_start(struct bio *bio) struct blkg_iostat_set *bis; unsigned long flags; - cpu = get_cpu(); + cpu = get_cpu_light(); bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu); flags = u64_stats_update_begin_irqsave(&bis->sync); @@ -1928,7 +1928,7 @@ void blk_cgroup_bio_start(struct bio *bio) u64_stats_update_end_irqrestore(&bis->sync, flags); if (cgroup_subsys_on_dfl(io_cgrp_subsys)) cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu); - put_cpu(); + put_cpu_light(); } static int __init blkcg_init(void)
This was caught during QA test: BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:942 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 243401, name: sed INFO: lockdep is turned off. Preemption disabled at: [<ffffffff89b26268>] blk_cgroup_bio_start+0x28/0xd0 CPU: 2 PID: 243401 Comm: sed Kdump: loaded Not tainted 4.18.0-353.rt7.138.el8.x86_64+debug #1 Hardware name: HP ProLiant DL380 Gen9, BIOS P89 05/06/2015 Call Trace: dump_stack+0x5c/0x80 ___might_sleep.cold.89+0xf5/0x109 rt_spin_lock+0x3e/0xd0 ? __blk_add_trace+0x428/0x4b0 __blk_add_trace+0x428/0x4b0 blk_add_trace_bio+0x16e/0x1c0 generic_make_request_checks+0x7e8/0x8c0 generic_make_request+0x3c/0x420 ? membarrier_private_expedited+0xd0/0x2b0 ? lock_release+0x1ca/0x450 ? submit_bio+0x3c/0x160 ? _raw_spin_unlock_irqrestore+0x3c/0x80 submit_bio+0x3c/0x160 ? rt_mutex_futex_unlock+0x66/0xa0 iomap_submit_ioend.isra.36+0x4a/0x70 xfs_vm_writepages+0x65/0x90 [xfs] do_writepages+0x41/0xe0 ? rt_mutex_futex_unlock+0x66/0xa0 __filemap_fdatawrite_range+0xce/0x110 xfs_release+0x11c/0x160 [xfs] __fput+0xd5/0x270 task_work_run+0xa1/0xd0 exit_to_usermode_loop+0x14d/0x160 do_syscall_64+0x23b/0x240 entry_SYSCALL_64_after_hwframe+0x6a/0xdf We replace the get/put_cpu() call by get/put_cpu_light to avoid this bug. Signed-off-by: Wander Lairson Costa <wander@redhat.com> --- block/blk-cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)