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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 16A801A0020 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: zyn6fpppx4aqhy6qcfz14ph6e5bxs1ce X-HE-Tag: 1728893631-697459 X-HE-Meta: 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 EvrtWcFp 1nWvDfOGKK5F8tukPITwsvOWLHkh+5M+sNdbr6VqizXukg4MPqxqFhOE7toqoPuAIcBkrG+aEAOH0yEz+oBDQBJRRMq790Q//GMBTI3R7mrhTFobfw+qnobUCBcwfjE+GJsSSCfSPT0Hu6UmIjP//m2EMi1l6+ThOa3kSyB/3kji9gBehpDUsryK9vXAQbo3Aw/cik8Ou6kN5C0lg5uc257HAoA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 10/14/24 08:53, Chen Ridong wrote: > From: Chen Ridong > > 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): > [] __kmalloc_node_noprof+0x394/0x470 > [] alloc_shrinker_info+0x7b/0x1a0 > [] mem_cgroup_css_online+0x11a/0x3b0 > [] online_css+0x29/0xa0 > [] cgroup_apply_control_enable+0x20d/0x360 > [] cgroup_mkdir+0x168/0x5f0 > [] kernfs_iop_mkdir+0x5e/0x90 > [] vfs_mkdir+0x144/0x220 > [] do_mkdirat+0x87/0x130 > [] __x64_sys_mkdir+0x49/0x70 > [] do_syscall_64+0x68/0x140 > [] 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 > --- > mm/shrinker.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/shrinker.c b/mm/shrinker.c > index dc5d2a6fcfc4..92270413190d 100644 > --- a/mm/shrinker.c > +++ b/mm/shrinker.c > @@ -97,6 +97,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) > > err: > mutex_unlock(&shrinker_mutex); > + kvfree(info); > free_shrinker_info(memcg); > return -ENOMEM; > } There are two scenarios when "goto err:" gets called - When shrinker_info allocations fails, no kvfree() is required - but after this change kvfree() would be called even when the allocation had failed originally, which does not sound right - shrinker_unit_alloc() fails, kvfree() is actually required I guess kvfree() should be called just after shrinker_unit_alloc() fails but before calling into "goto err". But curious, should not both kvzalloc_node()/kvfree() be avoided while inside mutex lock to avoid possible lockdep issues ?