Commit 8d58881b authored by Bart Van Assche's avatar Bart Van Assche Committed by Martin K. Petersen

scsi: Avoid that toggling use_blk_mq triggers a memory leak

This patch avoids that the following memory leak is triggered if
use_blk_mq is disabled after a SCSI host has been allocated by the
ib_srp driver and before the same SCSI host is freed:

unreferenced object 0xffff8803a168c568 (size 256):
    [<ffffffff81620c95>] kmemleak_alloc+0x45/0xa0
    [<ffffffff811bb104>] __kmalloc_node+0x1e4/0x400
    [<ffffffff81309fe4>] blk_mq_alloc_tag_set+0xb4/0x230
    [<ffffffff814731b7>] scsi_mq_setup_tags+0xc7/0xd0
    [<ffffffff81469c26>] scsi_add_host_with_dma+0x216/0x2d0
    [<ffffffffa064bef5>] srp_create_target+0xe55/0x13d0 [ib_srp]
    [<ffffffff8143ce23>] dev_attr_store+0x13/0x20
    [<ffffffff8125f030>] sysfs_kf_write+0x40/0x50
    [<ffffffff8125e397>] kernfs_fop_write+0x137/0x1c0
    [<ffffffff811d8c13>] __vfs_write+0x23/0x140
    [<ffffffff811d92e0>] vfs_write+0xb0/0x190
    [<ffffffff811da5b4>] SyS_write+0x44/0xa0
    [<ffffffff8162c8a5>] entry_SYSCALL_64_fastpath+0x18/0xa8

Fixes: 9aa9cc42 ("scsi: remove the disable_blk_mq host flag")
Signed-off-by: default avatarBart Van Assche <>
Cc: Christoph Hellwig <>
Cc: Martin K. Petersen <>
Cc: <>
Reviewed-by: default avatarChristoph Hellwig <>
Signed-off-by: default avatarMartin K. Petersen <>
parent a0f81dbe
......@@ -486,6 +486,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
shost->dma_boundary = 0xffffffff;
shost->use_blk_mq = scsi_use_blk_mq;
dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
shost->shost_gendev.bus = &scsi_bus_type;
......@@ -1160,7 +1160,6 @@ bool scsi_use_blk_mq = true;
bool scsi_use_blk_mq = false;
module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
static int __init init_scsi(void)
......@@ -29,6 +29,7 @@ extern int scsi_init_hosts(void);
extern void scsi_exit_hosts(void);
/* scsi.c */
extern bool scsi_use_blk_mq;
extern int scsi_setup_command_freelist(struct Scsi_Host *shost);
extern void scsi_destroy_command_freelist(struct Scsi_Host *shost);
......@@ -771,12 +771,9 @@ static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
extern bool scsi_use_blk_mq;
static inline bool shost_use_blk_mq(struct Scsi_Host *shost)
return scsi_use_blk_mq;
return shost->use_blk_mq;
extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
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