On Wed, 2015-11-18 at 14:56 -0800, Bart Van Assche wrote:
> Avoid that kmemleak reports the following memory leak if a
> SCSI LLD calls scsi_host_alloc() and scsi_host_put() but neither
> scsi_host_add() nor scsi_host_remove(). The following shell
> command triggers that scenario:
>
> for ((i=0; i<2; i++)); do
> srp_daemon -oac |
> while read line; do
> echo $line >/sys/class/infiniband_srp/srp-mlx4_0-1/add_target
> done
> done
>
> unreferenced object 0xffff88021b24a220 (size 8):
> comm "srp_daemon", pid 56421, jiffies 4295006762 (age 4240.750s)
> hex dump (first 8 bytes):
> 68 6f 73 74 35 38 00 a5 host58..
> backtrace:
> [<ffffffff8151014a>] kmemleak_alloc+0x7a/0xc0
> [<ffffffff81165c1e>] __kmalloc_track_caller+0xfe/0x160
> [<ffffffff81260d2b>] kvasprintf+0x5b/0x90
> [<ffffffff81260e2d>] kvasprintf_const+0x8d/0xb0
> [<ffffffff81254b0c>] kobject_set_name_vargs+0x3c/0xa0
> [<ffffffff81337e3c>] dev_set_name+0x3c/0x40
> [<ffffffff81355757>] scsi_host_alloc+0x327/0x4b0
> [<ffffffffa03edc8e>] srp_create_target+0x4e/0x8a0 [ib_srp]
> [<ffffffff8133778b>] dev_attr_store+0x1b/0x20
> [<ffffffff811f27fa>] sysfs_kf_write+0x4a/0x60
> [<ffffffff811f1e8e>] kernfs_fop_write+0x14e/0x180
> [<ffffffff81176eef>] __vfs_write+0x2f/0xf0
> [<ffffffff811771e4>] vfs_write+0xa4/0x100
> [<ffffffff81177c64>] SyS_write+0x54/0xc0
> [<ffffffff8151b257>] entry_SYSCALL_64_fastpath+0x12/0x6f
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxx>
> Cc: stable <stable@xxxxxxxxxxxxxxx>
> ---
> drivers/scsi/hosts.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index 323982f..82ac1cd 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -333,6 +333,17 @@ static void scsi_host_dev_release(struct device
> *dev)
> kfree(queuedata);
> }
>
> + if (shost->shost_state == SHOST_CREATED) {
> + /*
> + * Free the shost_dev device name here if
> scsi_host_alloc()
> + * and scsi_host_put() have been called but neither
> + * scsi_host_add() nor scsi_host_remove() has been
> called.
> + * This avoids that the memory allocated for the
> shost_dev
> + * name is leaked.
> + */
> + kfree(dev_name(&shost->shost_dev));
> + }
> +
> scsi_destroy_command_freelist(shost);
> if (shost_use_blk_mq(shost)) {
> if (shost->tag_set.tags)
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
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