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authorBart Van Assche <bvanassche@acm.org>2022-06-13 14:44:42 -0700
committerMartin K. Petersen <martin.petersen@oracle.com>2022-06-16 21:32:09 -0400
commit2acd76e7b8596e307fcec8fc6bc5fe5ab174749a (patch)
treeab433f7c9028d65a9d12c9e916b3b6b137c7aef1 /drivers/ufs
parentd1a7644648b7cdacaf8d1013a4285001911e9bc8 (diff)
downloadlinux-2acd76e7b8596e307fcec8fc6bc5fe5ab174749a.tar.bz2
scsi: ufs: Fix a race between the interrupt handler and the reset handler
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 an 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 Link: https://lore.kernel.org/r/20220613214442.212466-4-bvanassche@acm.org Reviewed-by: Stanley Chu <stanley.chu@mediatek.com> Reviewed-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/ufs')
-rw-r--r--drivers/ufs/core/ufshcd.c28
1 files changed, 19 insertions, 9 deletions
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 8789147760ae..ce86d1b790c0 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -6968,14 +6968,14 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
}
/**
- * ufshcd_eh_device_reset_handler - device reset handler registered to
- * scsi layer.
+ * ufshcd_eh_device_reset_handler() - Reset a single logical unit.
* @cmd: SCSI command pointer
*
* Returns SUCCESS/FAILED
*/
static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
{
+ unsigned long flags, pending_reqs = 0, not_cleared = 0;
struct Scsi_Host *host;
struct ufs_hba *hba;
u32 pos;
@@ -6994,14 +6994,24 @@ 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_cmds(hba, 1U << 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, &pending_reqs);
+ hba->outstanding_reqs &= ~pending_reqs;
+ spin_unlock_irqrestore(&hba->outstanding_lock, flags);
+
+ if (ufshcd_clear_cmds(hba, pending_reqs) < 0) {
+ spin_lock_irqsave(&hba->outstanding_lock, flags);
+ not_cleared = pending_reqs &
+ ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+ hba->outstanding_reqs |= not_cleared;
+ spin_unlock_irqrestore(&hba->outstanding_lock, flags);
+
+ dev_err(hba->dev, "%s: failed to clear requests %#lx\n",
+ __func__, not_cleared);
}
+ __ufshcd_transfer_req_compl(hba, pending_reqs & ~not_cleared);
out:
hba->req_abort_count = 0;