* [PATCH] lost path_put in perf_fill_ns_link_info
@ 2017-11-06 6:22 Vasily Averin
2017-11-06 6:34 ` Vasily Averin
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Vasily Averin @ 2017-11-06 6:22 UTC (permalink / raw)
To: linux-kernel, Hari Bathini
Cc: Namhyung Kim, Jiri Olsa, Alexander Shishkin,
Arnaldo Carvalho de Melo, Ingo Molnar, Peter Zijlstra
Fixes: commit e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include namespaces related info")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
kernel/events/core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 10cdb9c..ab5ac84 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6756,6 +6756,7 @@ static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
ns_inode = ns_path.dentry->d_inode;
ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
ns_link_info->ino = ns_inode->i_ino;
+ path_put(&ns_path);
}
}
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] lost path_put in perf_fill_ns_link_info 2017-11-06 6:22 [PATCH] lost path_put in perf_fill_ns_link_info Vasily Averin @ 2017-11-06 6:34 ` Vasily Averin 2017-11-07 19:03 ` Andrei Vagin [not found] ` <20171108120915.n7i46j2yly6fb7bj@ukko.fi.intel.com> 2 siblings, 0 replies; 6+ messages in thread From: Vasily Averin @ 2017-11-06 6:34 UTC (permalink / raw) To: linux-kernel, Hari Bathini Cc: Namhyung Kim, Jiri Olsa, Alexander Shishkin, Arnaldo Carvalho de Melo, Ingo Molnar, Peter Zijlstra Dear Hari, I did not found where your patch decreases mnt counter, it seems for me you have lost path_put in perf_fill_ns_link_info(). Thank you, Vasily Averin On 2017-11-06 09:22, Vasily Averin wrote: > Fixes: commit e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include namespaces related info") > Signed-off-by: Vasily Averin <vvs@virtuozzo.com> > --- > kernel/events/core.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 10cdb9c..ab5ac84 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -6756,6 +6756,7 @@ static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, > ns_inode = ns_path.dentry->d_inode; > ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); > ns_link_info->ino = ns_inode->i_ino; > + path_put(&ns_path); > } > } > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: lost path_put in perf_fill_ns_link_info 2017-11-06 6:22 [PATCH] lost path_put in perf_fill_ns_link_info Vasily Averin 2017-11-06 6:34 ` Vasily Averin @ 2017-11-07 19:03 ` Andrei Vagin 2017-11-07 19:51 ` Andrei Vagin [not found] ` <20171108120915.n7i46j2yly6fb7bj@ukko.fi.intel.com> 2 siblings, 1 reply; 6+ messages in thread From: Andrei Vagin @ 2017-11-07 19:03 UTC (permalink / raw) To: Vasily Averin Cc: linux-kernel, Hari Bathini, Namhyung Kim, Jiri Olsa, Alexander Shishkin, Arnaldo Carvalho de Melo, Ingo Molnar, Peter Zijlstra Hi Vasily and all, The patch looks correct for me. I tried to reproduce this issue and checked that this patch fixes it. Bellow you can find my test program and a command line to run it. The problem still exists even with this patch. $ cat test.c #define _GNU_SOURCE #include <sched.h> int main(int argc, char **argv) { while (1) unshare(CLONE_NEWUTS); return 0; } $ gcc -o test_unshare test.c $ for i in `seq 10000`; do perf trace -o log unshare -u true; done & [5] 28766 $ for i in `seq 10000`; do perf trace -o log unshare -u true; done & [6] 28840 $ echo 3 > /proc/sys/vm/drop_caches | cat /proc/slabinfo | grep dentry dentry 74848 78660 224 18 1 : tunables 0 0 0 : slabdata 4370 4370 0 $ sleep 10 $ echo 3 > /proc/sys/vm/drop_caches | cat /proc/slabinfo | grep dentry dentry 75145 79002 224 18 1 : tunables 0 0 0 : slabdata 4389 4389 0 $ sleep 10 $ echo 3 > /proc/sys/vm/drop_caches | cat /proc/slabinfo | grep dentry dentry 75921 79776 224 18 1 : tunables 0 0 0 : slabdata 4432 4432 0 $ git log --pretty=oneline | head -n 2 c83bceb10b36cef895def4b2dfe0aff6ca7c9784 lost path_put in perf_fill_ns_link_info 8b82a8a7ab53ee1a065ac69c835737a701f46b2e Add linux-next specific files for 20171107 Thanks, Andrei On Mon, Nov 06, 2017 at 09:22:18AM +0300, Vasily Averin wrote: > Fixes: commit e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include namespaces related info") > Signed-off-by: Vasily Averin <vvs@virtuozzo.com> > --- > kernel/events/core.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 10cdb9c..ab5ac84 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -6756,6 +6756,7 @@ static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, > ns_inode = ns_path.dentry->d_inode; > ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); > ns_link_info->ino = ns_inode->i_ino; > + path_put(&ns_path); > } > } > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: lost path_put in perf_fill_ns_link_info 2017-11-07 19:03 ` Andrei Vagin @ 2017-11-07 19:51 ` Andrei Vagin 0 siblings, 0 replies; 6+ messages in thread From: Andrei Vagin @ 2017-11-07 19:51 UTC (permalink / raw) To: Vasily Averin Cc: linux-kernel, Hari Bathini, Namhyung Kim, Jiri Olsa, Alexander Shishkin, Arnaldo Carvalho de Melo, Ingo Molnar, Peter Zijlstra On Tue, Nov 07, 2017 at 11:03:18AM -0800, Andrei Vagin wrote: > Hi Vasily and all, > > The patch looks correct for me. I tried to reproduce this issue and > checked that this patch fixes it. Bellow you can find my test program > and a command line to run it. The problem still exists even with this patch. > > $ cat test.c > #define _GNU_SOURCE > #include <sched.h> > > int main(int argc, char **argv) > { > while (1) > unshare(CLONE_NEWUTS); > return 0; > } > > $ gcc -o test_unshare test.c > $ for i in `seq 10000`; do perf trace -o log unshare -u true; done & > [5] 28766 > $ for i in `seq 10000`; do perf trace -o log unshare -u true; done & > [6] 28840 > > $ echo 3 > /proc/sys/vm/drop_caches | cat /proc/slabinfo | grep dentry > dentry 74848 78660 224 18 1 : tunables 0 0 0 : slabdata 4370 4370 0 > > $ sleep 10 > $ echo 3 > /proc/sys/vm/drop_caches | cat /proc/slabinfo | grep dentry > dentry 75145 79002 224 18 1 : tunables 0 0 0 : slabdata 4389 4389 0 > > $ sleep 10 > $ echo 3 > /proc/sys/vm/drop_caches | cat /proc/slabinfo | grep dentry > dentry 75921 79776 224 18 1 : tunables 0 0 0 : slabdata 4432 4432 0 Actually here is another issue, and it is reproduced by another script: for i in `seq 10000`; do perf trace -o /dev/null unshare -u true; done & And it is due to files what perf creates in /tmp //tmp/perf-vdso.so-84wDCZ //tmp/perf-vdso.so-YDfUuX //tmp/perf-vdso.so-KkTBfU //tmp/perf-vdso.so-srXfvU //tmp/perf-vdso.so-QrPscR //tmp/perf-vdso.so-wlxIZO //tmp/perf-vdso.so-ur4fBP //tmp/perf-vdso.so-gBMExN //tmp/perf-vdso.so-6sCehK //tmp/perf-vdso.so-cZ4GDK //tmp/perf-vdso.so-ImQLoH //tmp/perf-vdso.so-y4rMuF //tmp/perf-vdso.so-Wx1qIG //tmp/perf-vdso.so-g5mYOD ... Do we really need all these files? They all are identical. [root@fc24 ~]# diff -up /tmp/perf-vdso.so-fnVcRz /tmp/perf-vdso.so-FQGYzh [root@fc24 ~]# echo $? 0 > $ git log --pretty=oneline | head -n 2 > c83bceb10b36cef895def4b2dfe0aff6ca7c9784 lost path_put in perf_fill_ns_link_info > 8b82a8a7ab53ee1a065ac69c835737a701f46b2e Add linux-next specific files for 20171107 > > Thanks, > Andrei > > On Mon, Nov 06, 2017 at 09:22:18AM +0300, Vasily Averin wrote: > > Fixes: commit e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include namespaces related info") > > Signed-off-by: Vasily Averin <vvs@virtuozzo.com> > > --- > > kernel/events/core.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > index 10cdb9c..ab5ac84 100644 > > --- a/kernel/events/core.c > > +++ b/kernel/events/core.c > > @@ -6756,6 +6756,7 @@ static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, > > ns_inode = ns_path.dentry->d_inode; > > ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); > > ns_link_info->ino = ns_inode->i_ino; > > + path_put(&ns_path); > > } > > } > > ^ permalink raw reply [flat|nested] 6+ messages in thread
[parent not found: <20171108120915.n7i46j2yly6fb7bj@ukko.fi.intel.com>]
* Re: [PATCH] lost path_put in perf_fill_ns_link_info [not found] ` <20171108120915.n7i46j2yly6fb7bj@ukko.fi.intel.com> @ 2017-11-08 13:04 ` Vasily Averin 2017-11-15 5:48 ` Vasily Averin 0 siblings, 1 reply; 6+ messages in thread From: Vasily Averin @ 2017-11-08 13:04 UTC (permalink / raw) To: Alexander Shishkin Cc: linux-kernel, Hari Bathini, Namhyung Kim, Jiri Olsa, Arnaldo Carvalho de Melo, Ingo Molnar, Peter Zijlstra On 2017-11-08 15:09, Alexander Shishkin wrote: > On Mon, Nov 06, 2017 at 09:22:18AM +0300, Vasily Averin wrote: >> Fixes: commit e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include namespaces related info") >> Signed-off-by: Vasily Averin <vvs@virtuozzo.com> > > The change description is missing. One needs to open the source code and > look for proof of correctness for this patch. perf_fill_ns_link_info() calls ns_get_path() it returns ns_path with increased mnt and dentry counters. Problem is that nodody decrement these counters. You can call ./perf record --namespaces unshare -m and look how grows mount counter on nsfs_mnt. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] lost path_put in perf_fill_ns_link_info 2017-11-08 13:04 ` [PATCH] " Vasily Averin @ 2017-11-15 5:48 ` Vasily Averin 0 siblings, 0 replies; 6+ messages in thread From: Vasily Averin @ 2017-11-15 5:48 UTC (permalink / raw) To: Alexander Shishkin Cc: linux-kernel, Hari Bathini, Namhyung Kim, Jiri Olsa, Arnaldo Carvalho de Melo, Ingo Molnar, Peter Zijlstra On 2017-11-08 16:04, Vasily Averin wrote: > On 2017-11-08 15:09, Alexander Shishkin wrote: >> On Mon, Nov 06, 2017 at 09:22:18AM +0300, Vasily Averin wrote: >>> Fixes: commit e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include namespaces related info") >>> Signed-off-by: Vasily Averin <vvs@virtuozzo.com> >> >> The change description is missing. One needs to open the source code and >> look for proof of correctness for this patch. > > perf_fill_ns_link_info() calls ns_get_path() > it returns ns_path with increased mnt and dentry counters. > > Problem is that nodody decrement these counters. > > You can call ./perf record --namespaces unshare -m > and look how grows mount counter on nsfs_mnt. Situation is even worse, leaked dentry does not allow to free related namespaces. [root@localhost ~]# uname -a Linux localhost.localdomain 4.14.0+ #10 SMP Wed Nov 15 00:31:34 MSK 2017 x86_64 x86_64 x86_64 GNU/Linux VvS: without --namespace perf works correctly [root@localhost ~]# grep namespace /proc/slabinfo pid_namespace 0 0 2568 12 8 : tunables 0 0 0 : slabdata 0 0 0 user_namespace 0 0 824 39 8 : tunables 0 0 0 : slabdata 0 0 0 net_namespace 0 5 6272 5 8 : tunables 0 0 0 : slabdata 1 1 0 [root@localhost ~]# perf record -q unshare -n -U -p --fork true [root@localhost ~]# grep namespace /proc/slabinfo pid_namespace 0 12 2568 12 8 : tunables 0 0 0 : slabdata 1 1 0 user_namespace 0 39 824 39 8 : tunables 0 0 0 : slabdata 1 1 0 net_namespace 0 5 6272 5 8 : tunables 0 0 0 : slabdata 1 1 0 VvS: with --namespace perf leaks namespaces [root@localhost ~]# perf record -q --namespace unshare -n -U -p --fork true [root@localhost ~]# grep namespace /proc/slabinfo pid_namespace 1 12 2568 12 8 : tunables 0 0 0 : slabdata 1 1 0 user_namespace 1 39 824 39 8 : tunables 0 0 0 : slabdata 1 1 0 net_namespace 1 5 6272 5 8 : tunables 0 0 0 : slabdata 1 1 0 VvS: ... and once again, to be sure [root@localhost ~]# perf record -q --namespace unshare -n -U -p --fork true [root@localhost ~]# grep namespace /proc/slabinfo pid_namespace 2 12 2568 12 8 : tunables 0 0 0 : slabdata 1 1 0 user_namespace 2 39 824 39 8 : tunables 0 0 0 : slabdata 1 1 0 net_namespace 2 5 6272 5 8 : tunables 0 0 0 : slabdata 1 1 0 kmemleak also detects leaks dentry, inode, related structures and namespaces unreferenced object 0xffff998008e76738 (size 192): <<< dentry comm "unshare", pid 1436, jiffies 4294786539 (age 509.114s) [<ffffffffbb29f495>] __ns_get_path+0xf5/0x160 [<ffffffffbb29f5a8>] ns_get_path+0x28/0x50 [<ffffffffbb1adb00>] perf_fill_ns_link_info+0x20/0x80 [<ffffffffbb1b1ba7>] perf_event_namespaces.part.101+0xd7/0x120 [<ffffffffbb09e85d>] copy_process.part.34+0x171d/0x1ae0 [<ffffffffbb09eddc>] _do_fork+0xcc/0x390 [<ffffffffbb003a11>] do_syscall_64+0x61/0x170 [<ffffffffbb86e6fb>] return_from_SYSCALL_64+0x0/0x65 [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff998008e7c928 (size 600): <<< inode comm "unshare", pid 1436, jiffies 4294786539 (age 509.114s) [<ffffffffbb286f4e>] new_inode_pseudo+0xe/0x60 [<ffffffffbb29f3e2>] __ns_get_path+0x42/0x160 [<ffffffffbb29f5a8>] ns_get_path+0x28/0x50 ... unreferenced object 0xffff99800cacd320 (size 40): <<< inode_security_struct comm "unshare", pid 1436, jiffies 4294786539 (age 509.114s) [<ffffffffbb383876>] security_inode_alloc+0x36/0x50 [<ffffffffbb284bd5>] inode_init_always+0xf5/0x1d0 [<ffffffffbb28505b>] alloc_inode+0x2b/0x80 [<ffffffffbb286f4e>] new_inode_pseudo+0xe/0x60 [<ffffffffbb29f3e2>] __ns_get_path+0x42/0x160 ... unreferenced object 0xffff99800cb88a10 (size 2232): <<< pid_namespace comm "unshare", pid 1436, jiffies 4294786439 (age 509.214s) [<ffffffffbb0c0104>] create_new_namespaces+0xd4/0x1b0 [<ffffffffbb0c0359>] unshare_nsproxy_namespaces+0x59/0xb0 [<ffffffffbb09f415>] SyS_unshare+0x1e5/0x370 [<ffffffffbb86e673>] entry_SYSCALL_64_fastpath+0x1a/0x7d [<ffffffffffffffff>] 0xffffffffffffffff I've resend the patch as "[PATCH] memory leaks triggered by perf --namespace" Thank you, Vasily Averin ^ permalink raw reply [flat|nested] 6+ messages in thread
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2017-11-06 6:22 [PATCH] lost path_put in perf_fill_ns_link_info Vasily Averin
2017-11-06 6:34 ` Vasily Averin
2017-11-07 19:03 ` Andrei Vagin
2017-11-07 19:51 ` Andrei Vagin
[not found] ` <20171108120915.n7i46j2yly6fb7bj@ukko.fi.intel.com>
2017-11-08 13:04 ` [PATCH] " Vasily Averin
2017-11-15 5:48 ` Vasily Averin
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