[PATCH v1 1/1] ufs: core: fix shift issue in ufshcd_clear_cmd

[alice.chao]

From: Alice Chao <alice.chao@xxxxxxxxxxxx>

When task_tag > 32 (in mcq mode), 1U << task_tag will out of bound
for u32 mask. Fix this bug to prevent SHIFT_ISSUE (Bitwise shifts
that are out of bounds for their data type).

[name:debug_monitors&]Unexpected kernel BRK exception at EL1
[name:traps&]Internal error: BRK handler: 00000000f2005514 [#1] PREEMPT SMP
[name:mediatek_cpufreq_hw&]cpufreq stop DVFS log done
[name:mrdump&]Kernel Offset: 0x1ba5800000 from 0xffffffc008000000
[name:mrdump&]PHYS_OFFSET: 0x80000000
[name:mrdump&]pstate: 22400005 (nzCv daif +PAN -UAO)
[name:mrdump&]pc : [0xffffffdbaf52bb2c] ufshcd_clear_cmd+0x280/0x288
[name:mrdump&]lr : [0xffffffdbaf52a774] ufshcd_wait_for_dev_cmd+0x3e4/0x82c
[name:mrdump&]sp : ffffffc0081471b0
<snip>
Workqueue: ufs_eh_wq_0 ufshcd_err_handler
Call trace:
 dump_backtrace+0xf8/0x144
 show_stack+0x18/0x24
 dump_stack_lvl+0x78/0x9c
 dump_stack+0x18/0x44
 mrdump_common_die+0x254/0x480 [mrdump]
 ipanic_die+0x20/0x30 [mrdump]
 notify_die+0x15c/0x204
 die+0x10c/0x5f8
 arm64_notify_die+0x74/0x13c
 do_debug_exception+0x164/0x26c
 el1_dbg+0x64/0x80
 el1h_64_sync_handler+0x3c/0x90
 el1h_64_sync+0x68/0x6c
 ufshcd_clear_cmd+0x280/0x288
 ufshcd_wait_for_dev_cmd+0x3e4/0x82c
 ufshcd_exec_dev_cmd+0x5bc/0x9ac
 ufshcd_verify_dev_init+0x84/0x1c8
 ufshcd_probe_hba+0x724/0x1ce0
 ufshcd_host_reset_and_restore+0x260/0x574
 ufshcd_reset_and_restore+0x138/0xbd0
 ufshcd_err_handler+0x1218/0x2f28
 process_one_work+0x5fc/0x1140
 worker_thread+0x7d8/0xe20
 kthread+0x25c/0x468
 ret_from_fork+0x10/0x20

Signed-off-by: Alice Chao <alice.chao@xxxxxxxxxxxx>
---
 drivers/ufs/core/ufshcd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 029d017fc1b6..c6cff4aa440a 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -3057,7 +3057,7 @@ bool ufshcd_cmd_inflight(struct scsi_cmnd *cmd)
  */
 static int ufshcd_clear_cmd(struct ufs_hba *hba, u32 task_tag)
 {
-	u32 mask = 1U << task_tag;
+	u32 mask;
 	unsigned long flags;
 	int err;
 
@@ -3075,6 +3075,8 @@ static int ufshcd_clear_cmd(struct ufs_hba *hba, u32 task_tag)
 		return 0;
 	}
 
+	mask = 1U << task_tag;
+
 	/* clear outstanding transaction before retry */
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	ufshcd_utrl_clear(hba, mask);
-- 
2.18.0