From c7b2c5da000425ae11155d8f24c73ecbc0be6339 Mon Sep 17 00:00:00 2001 From: Warner Losh Date: Thu, 11 Mar 2021 08:42:44 -0700 Subject: [PATCH] nvme: use config_intrhook_drain to avoid removable card races nvme drives are configured early in boot. However, a number of the configuration steps takes which take a while, so we defer those to a config intrhook that runs before the root filesystem is mounted. At the same time, the PCI hot plug wakes up and tests the status of the card. It may decide that the card has gone away and deletes the child. As part of that process nvme_detach is called. If this call happens after the config_intrhook starts to run, but before it is finished, there's a race where we can tear down the device's soft state while the config_intrhook is still using it. Use the new config_intrhook_drain to disestablish the hook. Either it will be removed w/o running, or the routine will wait for it to finish. This closes the race and allows safe hotplug at any time, even very early in boot. Sponsored by: Netflix, Inc Reviewed by: jhb, mav Differential Revision: https://reviews.freebsd.org/D29006 (cherry picked from commit 8423f5d4c127f18e7500bc455bc7b6b1691385ef) --- sys/dev/nvme/nvme.c | 5 +---- sys/dev/nvme/nvme_ctrlr.c | 2 -- 2 files changed, 1 insertion(+), 6 deletions(-) diff --git a/sys/dev/nvme/nvme.c b/sys/dev/nvme/nvme.c index 3c145c817f8..f36125ba247 100644 --- a/sys/dev/nvme/nvme.c +++ b/sys/dev/nvme/nvme.c @@ -143,10 +143,7 @@ nvme_detach(device_t dev) { struct nvme_controller *ctrlr = DEVICE2SOFTC(dev); - if (ctrlr->config_hook.ich_arg != NULL) { - config_intrhook_disestablish(&ctrlr->config_hook); - ctrlr->config_hook.ich_arg = NULL; - } + config_intrhook_drain(&ctrlr->config_hook); nvme_ctrlr_destruct(ctrlr, dev); return (0); diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c index 9f86e3a8c84..b6befb2c88d 100644 --- a/sys/dev/nvme/nvme_ctrlr.c +++ b/sys/dev/nvme/nvme_ctrlr.c @@ -1134,7 +1134,6 @@ nvme_ctrlr_start_config_hook(void *arg) fail: nvme_ctrlr_fail(ctrlr); config_intrhook_disestablish(&ctrlr->config_hook); - ctrlr->config_hook.ich_arg = NULL; return; } @@ -1153,7 +1152,6 @@ fail: nvme_sysctl_initialize_ctrlr(ctrlr); config_intrhook_disestablish(&ctrlr->config_hook); - ctrlr->config_hook.ich_arg = NULL; ctrlr->is_initialized = 1; nvme_notify_new_controller(ctrlr);