From: Bart Van Assche Date: Thu, 4 Dec 2025 18:15:43 +0000 (-1000) Subject: scsi: ufs: core: Fix a deadlock in the frequency scaling code X-Git-Tag: v6.19-rc1~1^2~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d2875b812b141d0c449541976d92c8d89b94ec72;p=thirdparty%2Fkernel%2Flinux.git scsi: ufs: core: Fix a deadlock in the frequency scaling code Commit 08b12cda6c44 ("scsi: ufs: core: Switch to scsi_get_internal_cmd()") accidentally introduced a deadlock in the frequency scaling code. ufshcd_clock_scaling_unprepare() may submit a device management command while SCSI command processing is blocked. The deadlock was introduced by using the SCSI core for submitting device management commands (scsi_get_internal_cmd() + blk_execute_rq()). Fix this deadlock by calling blk_mq_unquiesce_tagset() before any device management commands are submitted by ufshcd_clock_scaling_unprepare(). Fixes: 08b12cda6c44 ("scsi: ufs: core: Switch to scsi_get_internal_cmd()") Reported-by: Manivannan Sadhasivam Reported-by: Roger Shimizu Closes: https://lore.kernel.org/linux-scsi/ehorjaflathzab5oekx2nae2zss5vi2r36yqkqsfjb2fgsifz2@yk3us5g3igow/ Tested-by: Roger Shimizu Cc: Nitin Rawat Signed-off-by: Bart Van Assche Reviewed-by: Peter Wang Reviewed-by: Nitin Rawat Tested-by: Alexey Klimov # RB5 board Link: https://patch.msgid.link/20251204181548.1006696-1-bvanassche@acm.org Signed-off-by: Martin K. Petersen --- diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 1837ae204d5e..80c0b49f30b0 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -1455,15 +1455,14 @@ out: static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, int err) { up_write(&hba->clk_scaling_lock); + mutex_unlock(&hba->wb_mutex); + blk_mq_unquiesce_tagset(&hba->host->tag_set); + mutex_unlock(&hba->host->scan_mutex); /* Enable Write Booster if current gear requires it else disable it */ if (ufshcd_enable_wb_if_scaling_up(hba) && !err) ufshcd_wb_toggle(hba, hba->pwr_info.gear_rx >= hba->clk_scaling.wb_gear); - mutex_unlock(&hba->wb_mutex); - - blk_mq_unquiesce_tagset(&hba->host->tag_set); - mutex_unlock(&hba->host->scan_mutex); ufshcd_release(hba); }