From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D69B26FAF; Tue, 5 Dec 2023 03:25:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="J4nWXUIU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AD5AC433C8; Tue, 5 Dec 2023 03:25:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1701746745; bh=uNd18zdkX9fUPXboyloMw6Uu2c1fLUglSeFsrN/T4dA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J4nWXUIU1E2k6F/bZNPwm0uqMPK8LCap5ZxpGqdd1kVG3BdCwzyMkQcD/CO26ags4 cCCWVk1ndUD0GWNl9PnApBNuxFPmNPOPfZpUHDLO6BLbA/Dt0mBmwW+9UUiFLm7op4 V274XX4evNDE0EEOKcFsyGhRzN0ixVz6AeznNp2g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dan Carpenter , Brett Creeley , Shannon Nelson , Alex Williamson , Sasha Levin Subject: [PATCH 6.6 132/134] vfio/pds: Fix possible sleep while in atomic context Date: Tue, 5 Dec 2023 12:16:44 +0900 Message-ID: <20231205031543.810960039@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231205031535.163661217@linuxfoundation.org> References: <20231205031535.163661217@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Brett Creeley [ Upstream commit ae2667cd8a479bb5abd6e24c12fcc9ef5bc06d75 ] The driver could possibly sleep while in atomic context resulting in the following call trace while CONFIG_DEBUG_ATOMIC_SLEEP=y is set: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:283 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2817, name: bash preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 Call Trace: dump_stack_lvl+0x36/0x50 __might_resched+0x123/0x170 mutex_lock+0x1e/0x50 pds_vfio_put_lm_file+0x1e/0xa0 [pds_vfio_pci] pds_vfio_put_save_file+0x19/0x30 [pds_vfio_pci] pds_vfio_state_mutex_unlock+0x2e/0x80 [pds_vfio_pci] pci_reset_function+0x4b/0x70 reset_store+0x5b/0xa0 kernfs_fop_write_iter+0x137/0x1d0 vfs_write+0x2de/0x410 ksys_write+0x5d/0xd0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 This can happen if pds_vfio_put_restore_file() and/or pds_vfio_put_save_file() grab the mutex_lock(&lm_file->lock) while the spin_lock(&pds_vfio->reset_lock) is held, which can happen during while calling pds_vfio_state_mutex_unlock(). Fix this by changing the reset_lock to reset_mutex so there are no such conerns. Also, make sure to destroy the reset_mutex in the driver specific VFIO device release function. This also fixes a spinlock bad magic BUG that was caused by not calling spinlock_init() on the reset_lock. Since, the lock is being changed to a mutex, make sure to call mutex_init() on it. Reported-by: Dan Carpenter Closes: https://lore.kernel.org/kvm/1f9bc27b-3de9-4891-9687-ba2820c1b390@moroto.mountain/ Fixes: bb500dbe2ac6 ("vfio/pds: Add VFIO live migration support") Signed-off-by: Brett Creeley Reviewed-by: Shannon Nelson Link: https://lore.kernel.org/r/20231122192532.25791-3-brett.creeley@amd.com Signed-off-by: Alex Williamson Signed-off-by: Sasha Levin --- drivers/vfio/pci/pds/pci_drv.c | 4 ++-- drivers/vfio/pci/pds/vfio_dev.c | 14 ++++++++------ drivers/vfio/pci/pds/vfio_dev.h | 2 +- 3 files changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/vfio/pci/pds/pci_drv.c b/drivers/vfio/pci/pds/pci_drv.c index ab4b5958e4131..caffa1a2cf591 100644 --- a/drivers/vfio/pci/pds/pci_drv.c +++ b/drivers/vfio/pci/pds/pci_drv.c @@ -55,10 +55,10 @@ static void pds_vfio_recovery(struct pds_vfio_pci_device *pds_vfio) * VFIO_DEVICE_STATE_RUNNING. */ if (deferred_reset_needed) { - spin_lock(&pds_vfio->reset_lock); + mutex_lock(&pds_vfio->reset_mutex); pds_vfio->deferred_reset = true; pds_vfio->deferred_reset_state = VFIO_DEVICE_STATE_ERROR; - spin_unlock(&pds_vfio->reset_lock); + mutex_unlock(&pds_vfio->reset_mutex); } } diff --git a/drivers/vfio/pci/pds/vfio_dev.c b/drivers/vfio/pci/pds/vfio_dev.c index 8c9fb87b13e1d..4c351c59d05a9 100644 --- a/drivers/vfio/pci/pds/vfio_dev.c +++ b/drivers/vfio/pci/pds/vfio_dev.c @@ -29,7 +29,7 @@ struct pds_vfio_pci_device *pds_vfio_pci_drvdata(struct pci_dev *pdev) void pds_vfio_state_mutex_unlock(struct pds_vfio_pci_device *pds_vfio) { again: - spin_lock(&pds_vfio->reset_lock); + mutex_lock(&pds_vfio->reset_mutex); if (pds_vfio->deferred_reset) { pds_vfio->deferred_reset = false; if (pds_vfio->state == VFIO_DEVICE_STATE_ERROR) { @@ -39,23 +39,23 @@ void pds_vfio_state_mutex_unlock(struct pds_vfio_pci_device *pds_vfio) } pds_vfio->state = pds_vfio->deferred_reset_state; pds_vfio->deferred_reset_state = VFIO_DEVICE_STATE_RUNNING; - spin_unlock(&pds_vfio->reset_lock); + mutex_unlock(&pds_vfio->reset_mutex); goto again; } mutex_unlock(&pds_vfio->state_mutex); - spin_unlock(&pds_vfio->reset_lock); + mutex_unlock(&pds_vfio->reset_mutex); } void pds_vfio_reset(struct pds_vfio_pci_device *pds_vfio) { - spin_lock(&pds_vfio->reset_lock); + mutex_lock(&pds_vfio->reset_mutex); pds_vfio->deferred_reset = true; pds_vfio->deferred_reset_state = VFIO_DEVICE_STATE_RUNNING; if (!mutex_trylock(&pds_vfio->state_mutex)) { - spin_unlock(&pds_vfio->reset_lock); + mutex_unlock(&pds_vfio->reset_mutex); return; } - spin_unlock(&pds_vfio->reset_lock); + mutex_unlock(&pds_vfio->reset_mutex); pds_vfio_state_mutex_unlock(pds_vfio); } @@ -156,6 +156,7 @@ static int pds_vfio_init_device(struct vfio_device *vdev) pds_vfio->vf_id = vf_id; mutex_init(&pds_vfio->state_mutex); + mutex_init(&pds_vfio->reset_mutex); vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P; vdev->mig_ops = &pds_vfio_lm_ops; @@ -177,6 +178,7 @@ static void pds_vfio_release_device(struct vfio_device *vdev) vfio_coredev.vdev); mutex_destroy(&pds_vfio->state_mutex); + mutex_destroy(&pds_vfio->reset_mutex); vfio_pci_core_release_dev(vdev); } diff --git a/drivers/vfio/pci/pds/vfio_dev.h b/drivers/vfio/pci/pds/vfio_dev.h index b8f2d667608f3..e7b01080a1ec3 100644 --- a/drivers/vfio/pci/pds/vfio_dev.h +++ b/drivers/vfio/pci/pds/vfio_dev.h @@ -18,7 +18,7 @@ struct pds_vfio_pci_device { struct pds_vfio_dirty dirty; struct mutex state_mutex; /* protect migration state */ enum vfio_device_mig_state state; - spinlock_t reset_lock; /* protect reset_done flow */ + struct mutex reset_mutex; /* protect reset_done flow */ u8 deferred_reset; enum vfio_device_mig_state deferred_reset_state; struct notifier_block nb; -- 2.42.0