2024-02-08 09:02:16

by Li Nan

Subject: [PATCH] md: fix kmemleak of rdev->serial

From: Li Nan <[email protected]>

If kobject_add() is fail in bind_rdev_to_array(), 'rdev->serial' will be
alloc not be freed, and kmemleak occurs.

unreferenced object 0xffff88815a350000 (size 49152):
comm "mdadm", pid 789, jiffies 4294716910
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc f773277a):
[<0000000058b0a453>] kmemleak_alloc+0x61/0xe0
[<00000000366adf14>] __kmalloc_large_node+0x15e/0x270
[<000000002e82961b>] __kmalloc_node.cold+0x11/0x7f
[<00000000f206d60a>] kvmalloc_node+0x74/0x150
[<0000000034bf3363>] rdev_init_serial+0x67/0x170
[<0000000010e08fe9>] mddev_create_serial_pool+0x62/0x220
[<00000000c3837bf0>] bind_rdev_to_array+0x2af/0x630
[<0000000073c28560>] md_add_new_disk+0x400/0x9f0
[<00000000770e30ff>] md_ioctl+0x15bf/0x1c10
[<000000006cfab718>] blkdev_ioctl+0x191/0x3f0
[<0000000085086a11>] vfs_ioctl+0x22/0x60
[<0000000018b656fe>] __x64_sys_ioctl+0xba/0xe0
[<00000000e54e675e>] do_syscall_64+0x71/0x150
[<000000008b0ad622>] entry_SYSCALL_64_after_hwframe+0x6c/0x74

Fixes: 963c555e75b0 ("md: introduce mddev_create/destroy_wb_pool for the change of member device")
Signed-off-by: Li Nan <[email protected]>
---
drivers/md/md.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index e05858653a41..350f5b22ba6f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2536,6 +2536,7 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
fail:
pr_warn("md: failed to register dev-%s for %s\n",
b, mdname(mddev));
+ mddev_destroy_serial_pool(mddev, rdev);
return err;
}

--
2.39.2

2024-02-12 23:24:22

by Song Liu

Subject: Re: [PATCH] md: fix kmemleak of rdev->serial

On Thu, Feb 8, 2024 at 1:00 AM <[email protected]> wrote:
>
> From: Li Nan <[email protected]>
>
> If kobject_add() is fail in bind_rdev_to_array(), 'rdev->serial' will be
> alloc not be freed, and kmemleak occurs.
>
> unreferenced object 0xffff88815a350000 (size 49152):
> comm "mdadm", pid 789, jiffies 4294716910
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace (crc f773277a):
> [<0000000058b0a453>] kmemleak_alloc+0x61/0xe0
> [<00000000366adf14>] __kmalloc_large_node+0x15e/0x270
> [<000000002e82961b>] __kmalloc_node.cold+0x11/0x7f
> [<00000000f206d60a>] kvmalloc_node+0x74/0x150
> [<0000000034bf3363>] rdev_init_serial+0x67/0x170
> [<0000000010e08fe9>] mddev_create_serial_pool+0x62/0x220
> [<00000000c3837bf0>] bind_rdev_to_array+0x2af/0x630
> [<0000000073c28560>] md_add_new_disk+0x400/0x9f0
> [<00000000770e30ff>] md_ioctl+0x15bf/0x1c10
> [<000000006cfab718>] blkdev_ioctl+0x191/0x3f0
> [<0000000085086a11>] vfs_ioctl+0x22/0x60
> [<0000000018b656fe>] __x64_sys_ioctl+0xba/0xe0
> [<00000000e54e675e>] do_syscall_64+0x71/0x150
> [<000000008b0ad622>] entry_SYSCALL_64_after_hwframe+0x6c/0x74
>
> Fixes: 963c555e75b0 ("md: introduce mddev_create/destroy_wb_pool for the change of member device")
> Signed-off-by: Li Nan <[email protected]>

LGTM. Applied to md-6.9.

Thanks,
Song