From ab0eec0ff0a421737a37f510ceab5c6ea59cd05a Mon Sep 17 00:00:00 2001 From: "Nikhil P. Rao" Date: Tue, 14 Jul 2026 18:02:22 +0000 Subject: pds_core: fix deadlock between reset thread and remove pci_reset_function() acquires device_lock before performing the reset. pdsc_remove() is called by the PCI core with device_lock already held. If pdsc_pci_reset_thread() is running when pdsc_remove() is called, destroy_workqueue() will block waiting for the work to complete, while the work is blocked waiting for device_lock - deadlock. Use pci_try_reset_function() which uses pci_dev_trylock() internally. This acquires both the device lock and the PCI config access lock without blocking - if either lock is contended, it returns -EAGAIN immediately. This avoids the deadlock while also ensuring proper config space access serialization during the reset. The pci_dev_get/put calls are also removed as they were unnecessary - the driver-owned workqueue is destroyed in pdsc_remove(), guaranteeing the work completes before remove returns. The PCI core holds its reference to pci_dev throughout the entire unbind sequence. Fixes: 81665adf25d2 ("pds_core: Fix pdsc_check_pci_health function to use work thread") Reported-by: sashiko-bot Closes: https://patchwork.kernel.org/comment/27002369/ Signed-off-by: Nikhil P. Rao Reviewed-by: Harshitha Ramamurthy Link: https://patch.msgid.link/20260714180223.1642792-2-nikhil.rao@amd.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/amd/pds_core/core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/amd/pds_core/core.c b/drivers/net/ethernet/amd/pds_core/core.c index 38a2446571af..1074a022a52f 100644 --- a/drivers/net/ethernet/amd/pds_core/core.c +++ b/drivers/net/ethernet/amd/pds_core/core.c @@ -606,9 +606,10 @@ void pdsc_pci_reset_thread(struct work_struct *work) struct pdsc *pdsc = container_of(work, struct pdsc, pci_reset_work); struct pci_dev *pdev = pdsc->pdev; - pci_dev_get(pdev); - pci_reset_function(pdev); - pci_dev_put(pdev); + /* Use try variant to avoid deadlock with pdsc_remove(). + * If lock is contended, the watchdog timer will retry. + */ + pci_try_reset_function(pdev); } static void pdsc_check_pci_health(struct pdsc *pdsc) -- cgit v1.2.3