On 11/06/22 02:29, Bart Van Assche wrote:
> Prevent that both the interrupt handler and the reset handler try to
> complete a request at the same time. This patch is the result of the
> analysis of the following crash:
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000120
> CPU: 0 PID: 0 Comm: swapper/0 Tainted: G OE 5.10.107-android13-4-00051-g1e48e8970cca-ab8664745 #1
> pc : ufshcd_release_scsi_cmd+0x30/0x46c
> lr : __ufshcd_transfer_req_compl+0x4fc/0x9c0
> Call trace:
> ufshcd_release_scsi_cmd+0x30/0x46c
> __ufshcd_transfer_req_compl+0x4fc/0x9c0
> ufshcd_poll+0xf0/0x208
> ufshcd_sl_intr+0xb8/0xf0
> ufshcd_intr+0x168/0x2f4
> __handle_irq_event_percpu+0xa0/0x30c
> handle_irq_event+0x84/0x178
> handle_fasteoi_irq+0x150/0x2e8
> __handle_domain_irq+0x114/0x1e4
> gic_handle_irq.31846+0x58/0x300
> el1_irq+0xe4/0x1c0
> cpuidle_enter_state+0x3ac/0x8c4
> do_idle+0x2fc/0x55c
> cpu_startup_entry+0x84/0x90
> kernel_init+0x0/0x310
> start_kernel+0x0/0x608
> start_kernel+0x4ec/0x608
>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> drivers/scsi/ufs/ufshcd.c | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 1fb3a8b9b03e..279691ff3562 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -6966,6 +6966,7 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
> */
> static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
> {
> + unsigned long flags, completed_reqs = 0;
> struct Scsi_Host *host;
> struct ufs_hba *hba;
> u32 pos;
> @@ -6984,13 +6985,18 @@ static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
> }
>
> /* clear the commands that were pending for corresponding LUN */
> - for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs) {
> - if (hba->lrb[pos].lun == lun) {
> - err = ufshcd_clear_cmd(hba, pos);
> - if (err)
> - break;
> - __ufshcd_transfer_req_compl(hba, 1U << pos);
> - }
> + spin_lock_irqsave(&hba->outstanding_lock, flags);
> + for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs)
> + if (hba->lrb[pos].lun == lun)
> + __set_bit(pos, &completed_reqs);
> + hba->outstanding_reqs &= ~completed_reqs;
> + spin_unlock_irqrestore(&hba->outstanding_lock, flags);
> +
> + for_each_set_bit(pos, &completed_reqs, hba->nutrs) {
> + err = ufshcd_clear_cmd(hba, pos);
> + if (err)
> + break;
Having cleared the bit in hba->outstanding_reqs, shouldn't we
always complete the request? i.e. we should not 'break' here
> + __ufshcd_transfer_req_compl(hba, 1U << pos);
> }
>
> out:
