From: "Ahmed S. Darwish" a.darwish@linutronix.de
mainline inclusion from mainline-master commit 18577cdcaeeb7a1ca5c3adc4d92ed2ba75699625 category: bugfix bugzilla: 175270 CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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hisi_sas_task_exec() uses preemptible() to see if it's safe to block. This does not work for CONFIG_PREEMPT_COUNT=n kernels in which preemptible() always returns 0.
The problem is masked when enabling some of the common Kconfig.debug options (like CONFIG_DEBUG_ATOMIC_SLEEP), as they implicitly enable the preemption counter.
In general, driver leaf functions should not make logic decisions based on the context they're called from. The caller should be the entity responsible for explicitly indicating context.
Since hisi_sas_task_exec() already has a gfp_t flags parameter, use it as the explicit context marker.
Link: https://lore.kernel.org/r/20201126132952.2287996-3-bigeasy@linutronix.de Fixes: 214e702d4b70 ("scsi: hisi_sas: Adjust task reject period during host reset") Fixes: 550c0d89d52d ("scsi: hisi_sas: Replace in_softirq() check in hisi_sas_task_exec()") Cc: Xiaofei Tan tanxiaofei@huawei.com Cc: Xiang Chen chenxiang66@hisilicon.com Cc: John Garry john.garry@huawei.com Acked-by: John Garry john.garry@huawei.com Signed-off-by: Ahmed S. Darwish a.darwish@linutronix.de Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Reviewed-by: Ouyangdelong ouyangdelong@huawei.com Signed-off-by: Nifujia nifujia1@hisilicon.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/scsi/hisi_sas/hisi_sas_main.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c index 95a4fc4f829d..edfe60856ee6 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_main.c +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c @@ -591,13 +591,7 @@ static int hisi_sas_task_exec(struct sas_task *task, gfp_t gfp_flags, dev = hisi_hba->dev;
if (unlikely(test_bit(HISI_SAS_REJECT_CMD_BIT, &hisi_hba->flags))) { - /* - * For IOs from upper layer, it may already disable preempt - * in the IO path, if disable preempt again in down(), - * function schedule() will report schedule_bug(), so check - * preemptible() before goto down(). - */ - if (!preemptible()) + if (!gfpflags_allow_blocking(gfp_flags)) return -EINVAL;
down(&hisi_hba->sem);