From e81478bbe7a1a062eeb5cd97cf00152a13ab8652 Mon Sep 17 00:00:00 2001 From: Kai Vehmanen Date: Wed, 10 Nov 2021 23:03:07 +0200 Subject: ALSA: hda: fix general protection fault in azx_runtime_idle Fix a corner case between PCI device driver remove callback and runtime PM idle callback. Following sequence of events can happen: - at azx_create, context is allocated with devm_kzalloc() and stored as pci_set_drvdata() - user-space requests to unbind audio driver - dd.c:__device_release_driver() calls PCI remove - pci-driver.c:pci_device_remove() calls the audio driver azx_remove() callback and this is completed - pci-driver.c:pm_runtime_put_sync() leads to a call to rpm_idle() which again calls azx_runtime_idle() - the azx context object, as returned by dev_get_drvdata(), is no longer valid -> access fault in azx_runtime_idle when executing struct snd_card *card = dev_get_drvdata(dev); chip = card->private_data; if (chip->disabled || hda->init_failed) This was discovered by i915_module_load test with 5.15.0 based linux-next tree. Example log caught by i915_module_load test with linux-next https://intel-gfx-ci.01.org/tree/linux-next/ <4> [264.038232] general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b73f0: 0000 [#1] PREEMPT SMP NOPTI <4> [264.038248] CPU: 0 PID: 5374 Comm: i915_module_loa Not tainted 5.15.0-next-20211109-gc8109c2ba35e-next-20211109 #1 [...] <4> [264.038267] RIP: 0010:azx_runtime_idle+0x12/0x60 [snd_hda_intel] [...] <4> [264.038355] Call Trace: <4> [264.038359] <4> [264.038362] __rpm_callback+0x3d/0x110 <4> [264.038371] rpm_idle+0x27f/0x380 <4> [264.038376] __pm_runtime_idle+0x3b/0x100 <4> [264.038382] pci_device_remove+0x6d/0xa0 <4> [264.038388] device_release_driver_internal+0xef/0x1e0 <4> [264.038395] unbind_store+0xeb/0x120 <4> [264.038400] kernfs_fop_write_iter+0x11a/0x1c0 Fix the issue by setting drvdata to NULL at end of azx_remove(). Signed-off-by: Kai Vehmanen Link: https://lore.kernel.org/r/20211110210307.1172004-1-kai.vehmanen@linux.intel.com Signed-off-by: Takashi Iwai --- sound/pci/hda/hda_intel.c | 1 + 1 file changed, 1 insertion(+) (limited to 'sound/pci/hda') diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index 90e9263ac0bd..fe51163f2d82 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -2365,6 +2365,7 @@ static void azx_remove(struct pci_dev *pci) cancel_delayed_work_sync(&hda->probe_work); device_lock(&pci->dev); + pci_set_drvdata(pci, NULL); snd_card_free(card); } } -- cgit v1.2.3-59-g8ed1b