| Message ID | 20241011142105.391157-1-chenridong@huaweicloud.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: shrinker: avoid memleak in alloc_shrinker_info | expand |
On 2024/10/11 22:21, Chen Ridong wrote: > From: Chen Ridong <chenridong@huawei.com> > > A memleak was found as bellow: > > unreferenced object 0xffff8881010d2a80 (size 32): > comm "mkdir", pid 1559, jiffies 4294932666 > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 @............... > backtrace (crc 2e7ef6fa): > [<ffffffff81372754>] __kmalloc_node_noprof+0x394/0x470 > [<ffffffff813024ab>] alloc_shrinker_info+0x7b/0x1a0 > [<ffffffff813b526a>] mem_cgroup_css_online+0x11a/0x3b0 > [<ffffffff81198dd9>] online_css+0x29/0xa0 > [<ffffffff811a243d>] cgroup_apply_control_enable+0x20d/0x360 > [<ffffffff811a5728>] cgroup_mkdir+0x168/0x5f0 > [<ffffffff8148543e>] kernfs_iop_mkdir+0x5e/0x90 > [<ffffffff813dbb24>] vfs_mkdir+0x144/0x220 > [<ffffffff813e1c97>] do_mkdirat+0x87/0x130 > [<ffffffff813e1de9>] __x64_sys_mkdir+0x49/0x70 > [<ffffffff81f8c928>] do_syscall_64+0x68/0x140 > [<ffffffff8200012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e > > In the alloc_shrinker_info function, when shrinker_unit_alloc return > err, the info won't be freed. Just fix it. > > Fixes: 307bececcd12 ("mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred}") I think this also needs to be cc'd to the stable mailing list: Cc: stable@vger.kernel.org > Signed-off-by: Chen Ridong <chenridong@huawei.com> > --- > mm/shrinker.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) Other than that, LGTM. Acked-by: Qi Zheng <zhengqi.arch@bytedance.com> Thanks! > > diff --git a/mm/shrinker.c b/mm/shrinker.c > index dc5d2a6fcfc4..e4b795ee6d2e 100644 > --- a/mm/shrinker.c > +++ b/mm/shrinker.c > @@ -87,8 +87,10 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) > if (!info) > goto err; > info->map_nr_max = shrinker_nr_max; > - if (shrinker_unit_alloc(info, NULL, nid)) > + if (shrinker_unit_alloc(info, NULL, nid)) { > + kvfree(info); > goto err; > + } > rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); > } > mutex_unlock(&shrinker_mutex);
> On Oct 11, 2024, at 22:21, Chen Ridong <chenridong@huaweicloud.com> wrote: > > From: Chen Ridong <chenridong@huawei.com> > > A memleak was found as bellow: > > unreferenced object 0xffff8881010d2a80 (size 32): > comm "mkdir", pid 1559, jiffies 4294932666 > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 @............... > backtrace (crc 2e7ef6fa): > [<ffffffff81372754>] __kmalloc_node_noprof+0x394/0x470 > [<ffffffff813024ab>] alloc_shrinker_info+0x7b/0x1a0 > [<ffffffff813b526a>] mem_cgroup_css_online+0x11a/0x3b0 > [<ffffffff81198dd9>] online_css+0x29/0xa0 > [<ffffffff811a243d>] cgroup_apply_control_enable+0x20d/0x360 > [<ffffffff811a5728>] cgroup_mkdir+0x168/0x5f0 > [<ffffffff8148543e>] kernfs_iop_mkdir+0x5e/0x90 > [<ffffffff813dbb24>] vfs_mkdir+0x144/0x220 > [<ffffffff813e1c97>] do_mkdirat+0x87/0x130 > [<ffffffff813e1de9>] __x64_sys_mkdir+0x49/0x70 > [<ffffffff81f8c928>] do_syscall_64+0x68/0x140 > [<ffffffff8200012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e > > In the alloc_shrinker_info function, when shrinker_unit_alloc return > err, the info won't be freed. Just fix it. > > Fixes: 307bececcd12 ("mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred}") > Signed-off-by: Chen Ridong <chenridong@huawei.com> > --- > mm/shrinker.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/shrinker.c b/mm/shrinker.c > index dc5d2a6fcfc4..e4b795ee6d2e 100644 > --- a/mm/shrinker.c > +++ b/mm/shrinker.c > @@ -87,8 +87,10 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) > if (!info) > goto err; > info->map_nr_max = shrinker_nr_max; > - if (shrinker_unit_alloc(info, NULL, nid)) > + if (shrinker_unit_alloc(info, NULL, nid)) { > + kvfree(info); > goto err; Since we already use goto to do the cleanup for failure, I don't like to mix two different ways to do the similar thing. I suggest adding the kvfree (BTW, it could handle NULL argument) to the label of err. Muchun, Thanks. > + } > rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); > } > mutex_unlock(&shrinker_mutex); > -- > 2.34.1 >
On 2024/10/12 10:42, Muchun Song wrote: > > >> On Oct 11, 2024, at 22:21, Chen Ridong <chenridong@huaweicloud.com> wrote: >> >> From: Chen Ridong <chenridong@huawei.com> >> >> A memleak was found as bellow: >> >> unreferenced object 0xffff8881010d2a80 (size 32): >> comm "mkdir", pid 1559, jiffies 4294932666 >> hex dump (first 32 bytes): >> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 @............... >> backtrace (crc 2e7ef6fa): >> [<ffffffff81372754>] __kmalloc_node_noprof+0x394/0x470 >> [<ffffffff813024ab>] alloc_shrinker_info+0x7b/0x1a0 >> [<ffffffff813b526a>] mem_cgroup_css_online+0x11a/0x3b0 >> [<ffffffff81198dd9>] online_css+0x29/0xa0 >> [<ffffffff811a243d>] cgroup_apply_control_enable+0x20d/0x360 >> [<ffffffff811a5728>] cgroup_mkdir+0x168/0x5f0 >> [<ffffffff8148543e>] kernfs_iop_mkdir+0x5e/0x90 >> [<ffffffff813dbb24>] vfs_mkdir+0x144/0x220 >> [<ffffffff813e1c97>] do_mkdirat+0x87/0x130 >> [<ffffffff813e1de9>] __x64_sys_mkdir+0x49/0x70 >> [<ffffffff81f8c928>] do_syscall_64+0x68/0x140 >> [<ffffffff8200012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e >> >> In the alloc_shrinker_info function, when shrinker_unit_alloc return >> err, the info won't be freed. Just fix it. >> >> Fixes: 307bececcd12 ("mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred}") >> Signed-off-by: Chen Ridong <chenridong@huawei.com> >> --- >> mm/shrinker.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/mm/shrinker.c b/mm/shrinker.c >> index dc5d2a6fcfc4..e4b795ee6d2e 100644 >> --- a/mm/shrinker.c >> +++ b/mm/shrinker.c >> @@ -87,8 +87,10 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) >> if (!info) >> goto err; >> info->map_nr_max = shrinker_nr_max; >> - if (shrinker_unit_alloc(info, NULL, nid)) >> + if (shrinker_unit_alloc(info, NULL, nid)) { >> + kvfree(info); >> goto err; > > Since we already use goto to do the cleanup for failure, I don't like > to mix two different ways to do the similar thing. I suggest adding > the kvfree (BTW, it could handle NULL argument) to the label of err. > > Muchun, > Thanks. > Thanks, I will update soon. Best regards, Ridong >> + } >> rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); >> } >> mutex_unlock(&shrinker_mutex); >> -- >> 2.34.1 >> >
diff --git a/mm/shrinker.c b/mm/shrinker.c index dc5d2a6fcfc4..e4b795ee6d2e 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -87,8 +87,10 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) if (!info) goto err; info->map_nr_max = shrinker_nr_max; - if (shrinker_unit_alloc(info, NULL, nid)) + if (shrinker_unit_alloc(info, NULL, nid)) { + kvfree(info); goto err; + } rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); } mutex_unlock(&shrinker_mutex);