From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76D63C4320A for ; Thu, 26 Aug 2021 16:23:27 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 43E9B6103A for ; Thu, 26 Aug 2021 16:23:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 43E9B6103A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 81DE56E881; Thu, 26 Aug 2021 16:23:25 +0000 (UTC) Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1027A6E02C; Thu, 26 Aug 2021 16:23:24 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10088"; a="198018629" X-IronPort-AV: E=Sophos;i="5.84,353,1620716400"; d="scan'208";a="198018629" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2021 09:23:20 -0700 X-IronPort-AV: E=Sophos;i="5.84,353,1620716400"; d="scan'208";a="527948190" Received: from jons-linux-dev-box.fm.intel.com (HELO jons-linux-dev-box) ([10.1.27.20]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2021 09:23:20 -0700 Date: Thu, 26 Aug 2021 09:18:11 -0700 From: Matthew Brost To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Cc: daniele.ceraolospurio@intel.com Subject: Re: [Intel-gfx] [PATCH 16/27] drm/i915: Allocate error capture in nowait context Message-ID: <20210826161811.GA19893@jons-linux-dev-box> References: <20210826032327.18078-1-matthew.brost@intel.com> <20210826032327.18078-17-matthew.brost@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210826032327.18078-17-matthew.brost@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Aug 25, 2021 at 08:23:16PM -0700, Matthew Brost wrote: > Error captures can now be done in a work queue processing G2H messages. > These messages need to be completely done being processed in the reset > path, to avoid races in the missing G2H cleanup, which create a > dependency on memory allocations and dma fences (i915_requests). > Requests depend on resets, thus now we have a circular dependency. To > work around this, allocate the error capture in a nowait context. > For completeness Daniel suggested we include the lockdep splat, included below: [ 154.625989] ====================================================== [ 154.632195] WARNING: possible circular locking dependency detected [ 154.638393] 5.14.0-rc5-guc+ #50 Tainted: G U [ 154.643991] ------------------------------------------------------ [ 154.650196] i915_selftest/1673 is trying to acquire lock: [ 154.655621] ffff8881079cb918 ((work_completion)(&ct->requests.worker)){+.+.}-{0:0}, at: __flush_work+0x350/0x4d0 [ 154.665826] but task is already holding lock: [ 154.671682] ffff8881079cbfb8 (>->reset.mutex){+.+.}-{3:3}, at: intel_gt_reset+0xf0/0x300 [i915] [ 154.680659] which lock already depends on the new lock. [ 154.688857] the existing dependency chain (in reverse order) is: [ 154.696365] -> #2 (>->reset.mutex){+.+.}-{3:3}: [ 154.702571] lock_acquire+0xd2/0x300 [ 154.706695] i915_gem_shrinker_taints_mutex+0x2d/0x50 [i915] [ 154.712959] intel_gt_init_reset+0x61/0x80 [i915] [ 154.718258] intel_gt_init_early+0xe6/0x120 [i915] [ 154.723648] i915_driver_probe+0x592/0xdc0 [i915] [ 154.728942] i915_pci_probe+0x43/0x1c0 [i915] [ 154.733891] pci_device_probe+0x9b/0x110 [ 154.738362] really_probe+0x1a6/0x3a0 [ 154.742568] __driver_probe_device+0xf9/0x170 [ 154.747468] driver_probe_device+0x19/0x90 [ 154.752114] __driver_attach+0x99/0x170 [ 154.756492] bus_for_each_dev+0x73/0xc0 [ 154.760870] bus_add_driver+0x14b/0x1f0 [ 154.765248] driver_register+0x67/0xb0 [ 154.769542] i915_init+0x18/0x8c [i915] [ 154.773964] do_one_initcall+0x53/0x2e0 [ 154.778343] do_init_module+0x56/0x210 [ 154.782639] load_module+0x25fc/0x29f0 [ 154.786934] __do_sys_finit_module+0xae/0x110 [ 154.791835] do_syscall_64+0x38/0xc0 [ 154.795958] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 154.801558] -> #1 (fs_reclaim){+.+.}-{0:0}: [ 154.807241] lock_acquire+0xd2/0x300 [ 154.811361] fs_reclaim_acquire+0x9e/0xd0 [ 154.815914] kmem_cache_alloc_trace+0x30/0x790 [ 154.820899] i915_gpu_coredump_alloc+0x53/0x1a0 [i915] [ 154.826649] i915_gpu_coredump+0x39/0x560 [i915] [ 154.831866] i915_capture_error_state+0xa/0x70 [i915] [ 154.837513] intel_guc_context_reset_process_msg+0x174/0x1f0 [i915] [ 154.844383] ct_incoming_request_worker_func+0x130/0x1b0 [i915] [ 154.850898] process_one_work+0x264/0x590 [ 154.855451] worker_thread+0x4b/0x3a0 [ 154.859655] kthread+0x147/0x170 [ 154.863428] ret_from_fork+0x1f/0x30 [ 154.867548] -> #0 ((work_completion)(&ct->requests.worker)){+.+.}-{0:0}: [ 154.875747] check_prev_add+0x90/0xc30 [ 154.880042] __lock_acquire+0x1643/0x2110 [ 154.884595] lock_acquire+0xd2/0x300 [ 154.888715] __flush_work+0x373/0x4d0 [ 154.892920] intel_guc_submission_reset_prepare+0xf3/0x340 [i915] [ 154.899606] intel_uc_reset_prepare+0x40/0x50 [i915] [ 154.905166] reset_prepare+0x55/0x60 [i915] [ 154.909946] intel_gt_reset+0x11c/0x300 [i915] [ 154.914984] do_device_reset+0x13/0x20 [i915] [ 154.919936] check_whitelist_across_reset+0x166/0x250 [i915] [ 154.926212] live_reset_whitelist.cold+0x6a/0x7a [i915] [ 154.932037] __i915_subtests.cold+0x20/0x74 [i915] [ 154.937428] __run_selftests.cold+0x96/0xee [i915] [ 154.942816] i915_live_selftests+0x2c/0x60 [i915] [ 154.948125] i915_pci_probe+0x93/0x1c0 [i915] [ 154.953076] pci_device_probe+0x9b/0x110 [ 154.957545] really_probe+0x1a6/0x3a0 [ 154.961749] __driver_probe_device+0xf9/0x170 [ 154.966653] driver_probe_device+0x19/0x90 [ 154.971290] __driver_attach+0x99/0x170 [ 154.975671] bus_for_each_dev+0x73/0xc0 [ 154.980053] bus_add_driver+0x14b/0x1f0 [ 154.984431] driver_register+0x67/0xb0 [ 154.988725] i915_init+0x18/0x8c [i915] [ 154.993149] do_one_initcall+0x53/0x2e0 [ 154.997527] do_init_module+0x56/0x210 [ 155.001822] load_module+0x25fc/0x29f0 [ 155.006118] __do_sys_finit_module+0xae/0x110 [ 155.011019] do_syscall_64+0x38/0xc0 [ 155.015139] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 155.020729] other info that might help us debug this: [ 155.028752] Chain exists of: (work_completion)(&ct->requests.worker) --> fs_reclaim --> >->reset.mutex [ 155.041294] Possible unsafe locking scenario: [ 155.047240] CPU0 CPU1 [ 155.051791] ---- ---- [ 155.056344] lock(>->reset.mutex); [ 155.060026] lock(fs_reclaim); [ 155.065706] lock(>->reset.mutex); [ 155.071912] lock((work_completion)(&ct->requests.worker)); [ 155.077595] *** DEADLOCK *** > v2: > (Daniel Vetter) > - Use GFP_NOWAIT instead GFP_ATOMIC > > Fixes: dc0dad365c5e ("Fix for error capture after full GPU reset with GuC") > Fixes: 573ba126aef3 ("Capture error state on context reset") > Signed-off-by: Matthew Brost > --- > drivers/gpu/drm/i915/i915_gpu_error.c | 39 +++++++++++++-------------- > 1 file changed, 19 insertions(+), 20 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c > index b9f66dbd46bb..8696ead02118 100644 > --- a/drivers/gpu/drm/i915/i915_gpu_error.c > +++ b/drivers/gpu/drm/i915/i915_gpu_error.c > @@ -49,8 +49,7 @@ > #include "i915_memcpy.h" > #include "i915_scatterlist.h" > > -#define ALLOW_FAIL (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN) > -#define ATOMIC_MAYFAIL (GFP_ATOMIC | __GFP_NOWARN) > +#define ATOMIC_MAYFAIL (GFP_NOWAIT | __GFP_NOWARN) > > static void __sg_set_buf(struct scatterlist *sg, > void *addr, unsigned int len, loff_t it) > @@ -79,7 +78,7 @@ static bool __i915_error_grow(struct drm_i915_error_state_buf *e, size_t len) > if (e->cur == e->end) { > struct scatterlist *sgl; > > - sgl = (typeof(sgl))__get_free_page(ALLOW_FAIL); > + sgl = (typeof(sgl))__get_free_page(ATOMIC_MAYFAIL); > if (!sgl) { > e->err = -ENOMEM; > return false; > @@ -99,10 +98,10 @@ static bool __i915_error_grow(struct drm_i915_error_state_buf *e, size_t len) > } > > e->size = ALIGN(len + 1, SZ_64K); > - e->buf = kmalloc(e->size, ALLOW_FAIL); > + e->buf = kmalloc(e->size, ATOMIC_MAYFAIL); > if (!e->buf) { > e->size = PAGE_ALIGN(len + 1); > - e->buf = kmalloc(e->size, GFP_KERNEL); > + e->buf = kmalloc(e->size, ATOMIC_MAYFAIL); > } > if (!e->buf) { > e->err = -ENOMEM; > @@ -243,12 +242,12 @@ static bool compress_init(struct i915_vma_compress *c) > { > struct z_stream_s *zstream = &c->zstream; > > - if (pool_init(&c->pool, ALLOW_FAIL)) > + if (pool_init(&c->pool, ATOMIC_MAYFAIL)) > return false; > > zstream->workspace = > kmalloc(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL), > - ALLOW_FAIL); > + ATOMIC_MAYFAIL); > if (!zstream->workspace) { > pool_fini(&c->pool); > return false; > @@ -256,7 +255,7 @@ static bool compress_init(struct i915_vma_compress *c) > > c->tmp = NULL; > if (i915_has_memcpy_from_wc()) > - c->tmp = pool_alloc(&c->pool, ALLOW_FAIL); > + c->tmp = pool_alloc(&c->pool, ATOMIC_MAYFAIL); > > return true; > } > @@ -280,7 +279,7 @@ static void *compress_next_page(struct i915_vma_compress *c, > if (dst->page_count >= dst->num_pages) > return ERR_PTR(-ENOSPC); > > - page = pool_alloc(&c->pool, ALLOW_FAIL); > + page = pool_alloc(&c->pool, ATOMIC_MAYFAIL); > if (!page) > return ERR_PTR(-ENOMEM); > > @@ -376,7 +375,7 @@ struct i915_vma_compress { > > static bool compress_init(struct i915_vma_compress *c) > { > - return pool_init(&c->pool, ALLOW_FAIL) == 0; > + return pool_init(&c->pool, ATOMIC_MAYFAIL) == 0; > } > > static bool compress_start(struct i915_vma_compress *c) > @@ -391,7 +390,7 @@ static int compress_page(struct i915_vma_compress *c, > { > void *ptr; > > - ptr = pool_alloc(&c->pool, ALLOW_FAIL); > + ptr = pool_alloc(&c->pool, ATOMIC_MAYFAIL); > if (!ptr) > return -ENOMEM; > > @@ -1026,7 +1025,7 @@ i915_vma_coredump_create(const struct intel_gt *gt, > > num_pages = min_t(u64, vma->size, vma->obj->base.size) >> PAGE_SHIFT; > num_pages = DIV_ROUND_UP(10 * num_pages, 8); /* worstcase zlib growth */ > - dst = kmalloc(sizeof(*dst) + num_pages * sizeof(u32 *), ALLOW_FAIL); > + dst = kmalloc(sizeof(*dst) + num_pages * sizeof(u32 *), ATOMIC_MAYFAIL); > if (!dst) > return NULL; > > @@ -1462,7 +1461,7 @@ capture_engine(struct intel_engine_cs *engine, > struct i915_request *rq = NULL; > unsigned long flags; > > - ee = intel_engine_coredump_alloc(engine, GFP_KERNEL); > + ee = intel_engine_coredump_alloc(engine, ATOMIC_MAYFAIL); > if (!ee) > return NULL; > > @@ -1510,7 +1509,7 @@ gt_record_engines(struct intel_gt_coredump *gt, > struct intel_engine_coredump *ee; > > /* Refill our page pool before entering atomic section */ > - pool_refill(&compress->pool, ALLOW_FAIL); > + pool_refill(&compress->pool, ATOMIC_MAYFAIL); > > ee = capture_engine(engine, compress); > if (!ee) > @@ -1536,7 +1535,7 @@ gt_record_uc(struct intel_gt_coredump *gt, > const struct intel_uc *uc = >->_gt->uc; > struct intel_uc_coredump *error_uc; > > - error_uc = kzalloc(sizeof(*error_uc), ALLOW_FAIL); > + error_uc = kzalloc(sizeof(*error_uc), ATOMIC_MAYFAIL); > if (!error_uc) > return NULL; > > @@ -1547,8 +1546,8 @@ gt_record_uc(struct intel_gt_coredump *gt, > * As modparams are generally accesible from the userspace make > * explicit copies of the firmware paths. > */ > - error_uc->guc_fw.path = kstrdup(uc->guc.fw.path, ALLOW_FAIL); > - error_uc->huc_fw.path = kstrdup(uc->huc.fw.path, ALLOW_FAIL); > + error_uc->guc_fw.path = kstrdup(uc->guc.fw.path, ATOMIC_MAYFAIL); > + error_uc->huc_fw.path = kstrdup(uc->huc.fw.path, ATOMIC_MAYFAIL); > error_uc->guc_log = > i915_vma_coredump_create(gt->_gt, > uc->guc.log.vma, "GuC log buffer", > @@ -1815,7 +1814,7 @@ i915_vma_capture_prepare(struct intel_gt_coredump *gt) > { > struct i915_vma_compress *compress; > > - compress = kmalloc(sizeof(*compress), ALLOW_FAIL); > + compress = kmalloc(sizeof(*compress), ATOMIC_MAYFAIL); > if (!compress) > return NULL; > > @@ -1848,11 +1847,11 @@ i915_gpu_coredump(struct intel_gt *gt, intel_engine_mask_t engine_mask) > if (IS_ERR(error)) > return error; > > - error = i915_gpu_coredump_alloc(i915, ALLOW_FAIL); > + error = i915_gpu_coredump_alloc(i915, ATOMIC_MAYFAIL); > if (!error) > return ERR_PTR(-ENOMEM); > > - error->gt = intel_gt_coredump_alloc(gt, ALLOW_FAIL); > + error->gt = intel_gt_coredump_alloc(gt, ATOMIC_MAYFAIL); > if (error->gt) { > struct i915_vma_compress *compress; > > -- > 2.32.0 >