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From: Andrew Morton <akpm@linux-foundation.org>
To: akash.goel@intel.com, akpm@linux-foundation.org,
	chris@chris-wilson.co.uk, dja@axtens.net, hulkci@huawei.com,
	linux-mm@kvack.org, mm-commits@vger.kernel.org,
	mpe@ellerman.id.au, rientjes@google.com, stable@vger.kernel.org,
	tglx@linutronix.de, torvalds@linux-foundation.org,
	viro@zeniv.linux.org.uk, walken@google.com,
	weiyongjun1@huawei.com
Subject: [patch 07/11] kernel/relay.c: fix memleak on destroy relay channel
Date: Thu, 20 Aug 2020 17:42:14 -0700	[thread overview]
Message-ID: <20200821004214.qRMMcztwG%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200820174132.67fd4a7a9359048f807a533b@linux-foundation.org>

From: Wei Yongjun <weiyongjun1@huawei.com>
Subject: kernel/relay.c: fix memleak on destroy relay channel

kmemleak report memory leak as follows:

unreferenced object 0x607ee4e5f948 (size 8):
comm "syz-executor.1", pid 2098, jiffies 4295031601 (age 288.468s)
hex dump (first 8 bytes):
00 00 00 00 00 00 00 00 ........
backtrace:
[<00000000ca1de2fa>] relay_open kernel/relay.c:583 [inline]
[<00000000ca1de2fa>] relay_open+0xb6/0x970 kernel/relay.c:563
[<0000000038ae5a4b>] do_blk_trace_setup+0x4a8/0xb20 kernel/trace/blktrace.c:557
[<00000000d5e778e9>] __blk_trace_setup+0xb6/0x150 kernel/trace/blktrace.c:597
[<0000000038fdf803>] blk_trace_ioctl+0x146/0x280 kernel/trace/blktrace.c:738
[<00000000ce25a0ca>] blkdev_ioctl+0xb2/0x6a0 block/ioctl.c:613
[<00000000579e47e0>] block_ioctl+0xe5/0x120 fs/block_dev.c:1871
[<00000000b1588c11>] vfs_ioctl fs/ioctl.c:48 [inline]
[<00000000b1588c11>] __do_sys_ioctl fs/ioctl.c:753 [inline]
[<00000000b1588c11>] __se_sys_ioctl fs/ioctl.c:739 [inline]
[<00000000b1588c11>] __x64_sys_ioctl+0x170/0x1ce fs/ioctl.c:739
[<0000000088fc9942>] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
[<000000004f6dd57a>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

'chan->buf' is malloced in relay_open() by alloc_percpu() but not free
while destroy the relay channel. Fix it by adding free_percpu() before
return from relay_destroy_channel().

Link: http://lkml.kernel.org/r/20200817122826.48518-1-weiyongjun1@huawei.com
Fixes: 017c59c042d0 ("relay: Use per CPU constructs for the relay channel buffer pointers")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: David Rientjes <rientjes@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Akash Goel <akash.goel@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/relay.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/relay.c~kernel-relayc-fix-memleak-on-destroy-relay-channel
+++ a/kernel/relay.c
@@ -197,6 +197,7 @@ free_buf:
 static void relay_destroy_channel(struct kref *kref)
 {
 	struct rchan *chan = container_of(kref, struct rchan, kref);
+	free_percpu(chan->buf);
 	kfree(chan);
 }
 
_


  parent reply	other threads:[~2020-08-21  0:42 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21  0:41 incoming Andrew Morton
2020-08-21  0:41 ` [patch 01/11] mailmap: add Andi Kleen Andrew Morton
2020-08-21  0:41 ` [patch 02/11] hugetlb_cgroup: convert comma to semicolon Andrew Morton
2020-08-21  0:42 ` [patch 03/11] khugepaged: adjust VM_BUG_ON_MM() in __khugepaged_enter() Andrew Morton
2020-08-21  0:42 ` [patch 04/11] mm/vunmap: add cond_resched() in vunmap_pmd_range Andrew Morton
2020-08-21  0:42 ` [patch 05/11] mm/rodata_test.c: fix missing function declaration Andrew Morton
2020-08-21  0:42 ` [patch 06/11] romfs: fix uninitialized memory leak in romfs_dev_read() Andrew Morton
2020-08-21  0:42 ` Andrew Morton [this message]
2020-08-21  0:42 ` [patch 08/11] uprobes: __replace_page() avoid BUG in munlock_vma_page() Andrew Morton
2020-08-21  0:42 ` [patch 09/11] squashfs: avoid bio_alloc() failure with 1Mbyte blocks Andrew Morton
2020-08-21  0:42 ` [patch 10/11] mm: include CMA pages in lowmem_reserve at boot Andrew Morton
2020-08-21  0:42 ` [patch 11/11] mm, page_alloc: fix core hung in free_pcppages_bulk() Andrew Morton

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