From patchwork Thu Mar 19 22:11:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11448131 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1710014B4 for ; Thu, 19 Mar 2020 22:11:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E123920782 for ; Thu, 19 Mar 2020 22:11:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="id27pi0B" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727425AbgCSWLw (ORCPT ); Thu, 19 Mar 2020 18:11:52 -0400 Received: from mail-wr1-f73.google.com ([209.85.221.73]:53220 "EHLO mail-wr1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727411AbgCSWLv (ORCPT ); Thu, 19 Mar 2020 18:11:51 -0400 Received: by mail-wr1-f73.google.com with SMTP id d17so1671523wrw.19 for ; Thu, 19 Mar 2020 15:11:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=BNxXtj/13XDbJ7Ka5VyV4F1h9//JX6ytXN0Nb1qnsrE=; b=id27pi0BKE21ye862UMlUIUsuloyLQnOaq47flGVBFu8NhiSN8iJGFuELhO9fL9c2i 3DrvAuZxJ7uG3R2yiWiVPLL73B1N59dm/Z80mOxbMZIZFIhXIPDoyNnqH5xsgNLIOffF +941+dhcc6Nfhs+StEbc4VztERyewJDbgZBqS94bNCFl69NQHAMezP3UboVU+6s46s2q +k/XeLO17v0Tfuqy8f/qzkayAHyeZpc6EPp3pewS0xJXR0F/1MHNGPIobNcTomXr5jzp yqlLXZ2LKHuE9OYGkte1TDW4v0RedlqKBLLtYEqp7gxi9DS5spWZgrgcPB5pbLCJTKTQ Qu0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=BNxXtj/13XDbJ7Ka5VyV4F1h9//JX6ytXN0Nb1qnsrE=; b=Eb16XCJO8hZJQe0965cR9ZTTdEANSdXjnguIwQTa9EO+5vBcFlHPMrC1wbAKkK0nHF 5eYpudnUk1M3aLLtbC/WLFGAjoX9tmQXdo7exejNV+e+8x5kmRyJ1i4uwdNfTi5ix91t JdvMtBgmuamdFaovnB6d3TEV9wrInSumzpqqazxHzBflwGscTMjIIhtzVBKrhKWBxDfs 9MREAlQLlYwj+U88Qcok6bC9e4SxnSoabNTqXvyZa19wmISYrYJBGTeCKioZYDRg7WF3 XWXFhcWqsf+y/GF8+Be3e316QAQ4312EM+wDAsSBxgtYe5Has7HXKvBlZx9phr9sIf1t R8jw== X-Gm-Message-State: ANhLgQ08g9miFTVw3sinvDzGiLxYacVwRxGWiJ3YF9rkgH30yeITqZrY cAcZbSFC+fhJ4BDVsFDbQlm/k4mapuXkfeU/ X-Google-Smtp-Source: ADFU+vtDV7twOz6cfedgfECl1aqVWSE+cPZjczrKqwiVgPhLXraJNbvYbTMR8e5CySx3P1IyGBOhlWHfXkkBdUJb X-Received: by 2002:a5d:4683:: with SMTP id u3mr6704253wrq.310.1584655909192; Thu, 19 Mar 2020 15:11:49 -0700 (PDT) Date: Thu, 19 Mar 2020 23:11:34 +0100 In-Reply-To: Message-Id: <4a497134b2cf7a9d306d28e3dd2746f5446d1605.1584655448.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v3 1/7] kcov: cleanup debug messages From: Andrey Konovalov To: Dmitry Vyukov Cc: Greg Kroah-Hartman , Alan Stern , Andrew Morton , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Potapenko , Marco Elver , Andrey Konovalov Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Previous commit left a lot of excessive debug messages, clean them up. Signed-off-by: Andrey Konovalov --- kernel/kcov.c | 22 ++-------------------- 1 file changed, 2 insertions(+), 20 deletions(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index f50354202dbe..f6bd119c9419 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -98,6 +98,7 @@ static struct kcov_remote *kcov_remote_find(u64 handle) return NULL; } +/* Must be called with kcov_remote_lock locked. */ static struct kcov_remote *kcov_remote_add(struct kcov *kcov, u64 handle) { struct kcov_remote *remote; @@ -119,16 +120,13 @@ static struct kcov_remote_area *kcov_remote_area_get(unsigned int size) struct kcov_remote_area *area; struct list_head *pos; - kcov_debug("size = %u\n", size); list_for_each(pos, &kcov_remote_areas) { area = list_entry(pos, struct kcov_remote_area, list); if (area->size == size) { list_del(&area->list); - kcov_debug("rv = %px\n", area); return area; } } - kcov_debug("rv = NULL\n"); return NULL; } @@ -136,7 +134,6 @@ static struct kcov_remote_area *kcov_remote_area_get(unsigned int size) static void kcov_remote_area_put(struct kcov_remote_area *area, unsigned int size) { - kcov_debug("area = %px, size = %u\n", area, size); INIT_LIST_HEAD(&area->list); area->size = size; list_add(&area->list, &kcov_remote_areas); @@ -366,7 +363,6 @@ static void kcov_remote_reset(struct kcov *kcov) hash_for_each_safe(kcov_remote_map, bkt, tmp, remote, hnode) { if (remote->kcov != kcov) continue; - kcov_debug("removing handle %llx\n", remote->handle); hash_del(&remote->hnode); kfree(remote); } @@ -553,7 +549,6 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, switch (cmd) { case KCOV_INIT_TRACE: - kcov_debug("KCOV_INIT_TRACE\n"); /* * Enable kcov in trace mode and setup buffer size. * Must happen before anything else. @@ -572,7 +567,6 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, kcov->mode = KCOV_MODE_INIT; return 0; case KCOV_ENABLE: - kcov_debug("KCOV_ENABLE\n"); /* * Enable coverage for the current task. * At this point user must have been enabled trace mode, @@ -598,7 +592,6 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, kcov_get(kcov); return 0; case KCOV_DISABLE: - kcov_debug("KCOV_DISABLE\n"); /* Disable coverage for the current task. */ unused = arg; if (unused != 0 || current->kcov != kcov) @@ -610,7 +603,6 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, kcov_put(kcov); return 0; case KCOV_REMOTE_ENABLE: - kcov_debug("KCOV_REMOTE_ENABLE\n"); if (kcov->mode != KCOV_MODE_INIT || !kcov->area) return -EINVAL; t = current; @@ -629,7 +621,6 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, kcov->remote_size = remote_arg->area_size; spin_lock(&kcov_remote_lock); for (i = 0; i < remote_arg->num_handles; i++) { - kcov_debug("handle %llx\n", remote_arg->handles[i]); if (!kcov_check_handle(remote_arg->handles[i], false, true, false)) { spin_unlock(&kcov_remote_lock); @@ -644,8 +635,6 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, } } if (remote_arg->common_handle) { - kcov_debug("common handle %llx\n", - remote_arg->common_handle); if (!kcov_check_handle(remote_arg->common_handle, true, false, false)) { spin_unlock(&kcov_remote_lock); @@ -782,7 +771,6 @@ void kcov_remote_start(u64 handle) spin_lock(&kcov_remote_lock); remote = kcov_remote_find(handle); if (!remote) { - kcov_debug("no remote found"); spin_unlock(&kcov_remote_lock); return; } @@ -810,8 +798,6 @@ void kcov_remote_start(u64 handle) /* Reset coverage size. */ *(u64 *)area = 0; - kcov_debug("area = %px, size = %u", area, size); - kcov_start(t, size, area, mode, sequence); } @@ -881,10 +867,8 @@ void kcov_remote_stop(void) unsigned int size = t->kcov_size; int sequence = t->kcov_sequence; - if (!kcov) { - kcov_debug("no kcov found\n"); + if (!kcov) return; - } kcov_stop(t); t->kcov = NULL; @@ -894,8 +878,6 @@ void kcov_remote_stop(void) * KCOV_DISABLE could have been called between kcov_remote_start() * and kcov_remote_stop(), hence the check. */ - kcov_debug("move if: %d == %d && %d\n", - sequence, kcov->sequence, (int)kcov->remote); if (sequence == kcov->sequence && kcov->remote) kcov_move_area(kcov->mode, kcov->area, kcov->size, area); spin_unlock(&kcov->lock); From patchwork Thu Mar 19 22:11:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11448135 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0EC661668 for ; Thu, 19 Mar 2020 22:12:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E0E2B20772 for ; Thu, 19 Mar 2020 22:12:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="vi4yd//X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727438AbgCSWMA (ORCPT ); Thu, 19 Mar 2020 18:12:00 -0400 Received: from mail-vs1-f74.google.com ([209.85.217.74]:42584 "EHLO mail-vs1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727459AbgCSWL7 (ORCPT ); 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Thu, 19 Mar 2020 15:11:56 -0700 (PDT) Date: Thu, 19 Mar 2020 23:11:36 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v3 2/7] kcov: fix potential use-after-free in kcov_remote_start From: Andrey Konovalov To: Dmitry Vyukov Cc: Greg Kroah-Hartman , Alan Stern , Andrew Morton , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Potapenko , Marco Elver , Andrey Konovalov , Andrey Konovalov Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Andrey Konovalov If vmalloc() fails in kcov_remote_start() we'll access remote->kcov without holding kcov_remote_lock, so remote might potentially be freed at that point. Cache kcov pointer in a local variable. Signed-off-by: Andrey Konovalov --- kernel/kcov.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index f6bd119c9419..cc5900ac2467 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -748,6 +748,7 @@ static const struct file_operations kcov_fops = { void kcov_remote_start(u64 handle) { struct kcov_remote *remote; + struct kcov *kcov; void *area; struct task_struct *t; unsigned int size; @@ -774,16 +775,17 @@ void kcov_remote_start(u64 handle) spin_unlock(&kcov_remote_lock); return; } + kcov = remote->kcov; /* Put in kcov_remote_stop(). */ - kcov_get(remote->kcov); - t->kcov = remote->kcov; + kcov_get(kcov); + t->kcov = kcov; /* * Read kcov fields before unlock to prevent races with * KCOV_DISABLE / kcov_remote_reset(). */ - size = remote->kcov->remote_size; - mode = remote->kcov->mode; - sequence = remote->kcov->sequence; + size = kcov->remote_size; + mode = kcov->mode; + sequence = kcov->sequence; area = kcov_remote_area_get(size); spin_unlock(&kcov_remote_lock); @@ -791,7 +793,7 @@ void kcov_remote_start(u64 handle) area = vmalloc(size * sizeof(unsigned long)); if (!area) { t->kcov = NULL; - kcov_put(remote->kcov); + kcov_put(kcov); return; } } From patchwork Thu Mar 19 22:11:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11448137 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2144E14B4 for ; Thu, 19 Mar 2020 22:12:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00F6620782 for ; Thu, 19 Mar 2020 22:12:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="K2+uoUuz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727488AbgCSWMD (ORCPT ); Thu, 19 Mar 2020 18:12:03 -0400 Received: from mail-qk1-f202.google.com ([209.85.222.202]:35208 "EHLO mail-qk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727485AbgCSWMD (ORCPT ); Thu, 19 Mar 2020 18:12:03 -0400 Received: by mail-qk1-f202.google.com with SMTP id m6so3818397qkm.2 for ; Thu, 19 Mar 2020 15:12:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=fIqMwS00THjQL8QKegGCqQ7wHnAdSxWfj9DzW584Lig=; b=K2+uoUuzJ7qI2VyHeBWbmnAMRTedq8vu6UUh0qMuX/hX0rQCZrdcenzFPHyt/0UMXh c8vqUce2QA0jAZqHiJTEsbpd/sD9ihzGcL3DRauiNPXn3TDDZkDsocqbkoJ1JX2I0DrW HCYA9rphqPDkklXCWXisz84yxStV3Ovhxsqg+ep5NTvVU7EcRKcdT5a3vfFpMkN5GWtK b2BlK2fs5LSHotHrkB9QukzkrsIkWz7Xt1q+oMbes/nC7F/99p3ukZZ2h2eLgjEjB0Pn XOFAO3zxOqHR//HYKX0DmuvJjRm45OFp56Z0MLBuon4BZvPyjjZqDSuqNFVwavAqXk5t bCQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=fIqMwS00THjQL8QKegGCqQ7wHnAdSxWfj9DzW584Lig=; b=UeOtEGYMeBHdFMesbYahOToo/56UbFoIIdTFrkvs1AIpBwukkgEMzqEZHlRZMLv2ct uFqtlvPBZ53GkiqgWqtegyuwBj/Ag2+Hb5fbu/MKXS9MCReq48SljbHalHy32lRlLUyc VsL9u2KutLcrvm0tNvObhLHWWB488LV2wVEVwQnv7nCLaUx5b/2zbdMGh5MKCDOAeDjP 1T/hCTHPu9i9AHW2UL7x5nsWuzi1gVXSLtR1WXzdc6dZALaT+yxmWlPPafJFoJ38ellh FL7huJKlZSRZ744ryKm1g7R11oGAnmb9dD49z+lTfLxAXl/eEVu0ezKmj/WS3nApnchZ FMlw== X-Gm-Message-State: ANhLgQ25ljWjobA4YIJPgTGVRk6YUV2bj9IADMdX2xjtcbOkdi5daziH 8JoZBTbX7SsdlopHAVQAKAuXEZUP6Vs4JhXC X-Google-Smtp-Source: ADFU+vtIWtDIAzLwtLZgt60qDzlAtH5D5+CqnrbWBsZPfua52L+P/AhW0RiO0jULC1lQ6jiz0Vs7L7bVGOSqhuAp X-Received: by 2002:a05:6214:10e5:: with SMTP id q5mr447241qvt.245.1584655919958; Thu, 19 Mar 2020 15:11:59 -0700 (PDT) Date: Thu, 19 Mar 2020 23:11:37 +0100 In-Reply-To: Message-Id: <82625ef3ff878f0b585763cc31d09d9b08ca37d6.1584655448.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v3 3/7] kcov: move t->kcov assignments into kcov_start/stop From: Andrey Konovalov To: Dmitry Vyukov Cc: Greg Kroah-Hartman , Alan Stern , Andrew Morton , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Potapenko , Marco Elver , Andrey Konovalov , Andrey Konovalov Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Andrey Konovalov Every time kcov_start/stop() is called, t->kcov is also assigned, so move the assignment into the functions. Signed-off-by: Andrey Konovalov --- kernel/kcov.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index cc5900ac2467..888d0a236b04 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -309,10 +309,12 @@ void notrace __sanitizer_cov_trace_switch(u64 val, u64 *cases) EXPORT_SYMBOL(__sanitizer_cov_trace_switch); #endif /* ifdef CONFIG_KCOV_ENABLE_COMPARISONS */ -static void kcov_start(struct task_struct *t, unsigned int size, - void *area, enum kcov_mode mode, int sequence) +static void kcov_start(struct task_struct *t, struct kcov *kcov, + unsigned int size, void *area, enum kcov_mode mode, + int sequence) { kcov_debug("t = %px, size = %u, area = %px\n", t, size, area); + t->kcov = kcov; /* Cache in task struct for performance. */ t->kcov_size = size; t->kcov_area = area; @@ -326,6 +328,7 @@ static void kcov_stop(struct task_struct *t) { WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED); barrier(); + t->kcov = NULL; t->kcov_size = 0; t->kcov_area = NULL; } @@ -333,7 +336,6 @@ static void kcov_stop(struct task_struct *t) static void kcov_task_reset(struct task_struct *t) { kcov_stop(t); - t->kcov = NULL; t->kcov_sequence = 0; t->kcov_handle = 0; } @@ -584,9 +586,8 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, return mode; kcov_fault_in_area(kcov); kcov->mode = mode; - kcov_start(t, kcov->size, kcov->area, kcov->mode, + kcov_start(t, kcov, kcov->size, kcov->area, kcov->mode, kcov->sequence); - t->kcov = kcov; kcov->t = t; /* Put either in kcov_task_exit() or in KCOV_DISABLE. */ kcov_get(kcov); @@ -778,7 +779,6 @@ void kcov_remote_start(u64 handle) kcov = remote->kcov; /* Put in kcov_remote_stop(). */ kcov_get(kcov); - t->kcov = kcov; /* * Read kcov fields before unlock to prevent races with * KCOV_DISABLE / kcov_remote_reset(). @@ -792,7 +792,6 @@ void kcov_remote_start(u64 handle) if (!area) { area = vmalloc(size * sizeof(unsigned long)); if (!area) { - t->kcov = NULL; kcov_put(kcov); return; } @@ -800,7 +799,7 @@ void kcov_remote_start(u64 handle) /* Reset coverage size. */ *(u64 *)area = 0; - kcov_start(t, size, area, mode, sequence); + kcov_start(t, kcov, size, area, mode, sequence); } EXPORT_SYMBOL(kcov_remote_start); @@ -873,7 +872,6 @@ void kcov_remote_stop(void) return; kcov_stop(t); - t->kcov = NULL; spin_lock(&kcov->lock); /* From patchwork Thu Mar 19 22:11:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11448139 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CDF881668 for ; Thu, 19 Mar 2020 22:12:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC06020782 for ; Thu, 19 Mar 2020 22:12:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ig3aTo8K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727507AbgCSWMH (ORCPT ); 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Signed-off-by: Andrey Konovalov --- kernel/kcov.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index 888d0a236b04..b985b7a72870 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -318,10 +318,10 @@ static void kcov_start(struct task_struct *t, struct kcov *kcov, /* Cache in task struct for performance. */ t->kcov_size = size; t->kcov_area = area; + t->kcov_sequence = sequence; /* See comment in check_kcov_mode(). */ barrier(); WRITE_ONCE(t->kcov_mode, mode); - t->kcov_sequence = sequence; } static void kcov_stop(struct task_struct *t) From patchwork Thu Mar 19 22:11:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11448141 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A7F5D1668 for ; Thu, 19 Mar 2020 22:12:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8700F20836 for ; Thu, 19 Mar 2020 22:12:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="pWhK7I5r" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727461AbgCSWMJ (ORCPT ); Thu, 19 Mar 2020 18:12:09 -0400 Received: from mail-wm1-f74.google.com ([209.85.128.74]:39594 "EHLO mail-wm1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727486AbgCSWMI (ORCPT ); Thu, 19 Mar 2020 18:12:08 -0400 Received: by mail-wm1-f74.google.com with SMTP id f8so1206483wmh.4 for ; Thu, 19 Mar 2020 15:12:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Pwl3VRG7l199xZxXoBkdQ57y28gQcRR32eC7hYs9l4c=; b=pWhK7I5rdncYloHW6Fkfx4nIo8X3qtdW2rxT6ih9yWpH4pobvweIuJDqvPUYPPO4iY 4pG5X3Qqv9W5F6idw4bdcmHH5SnzClP/tY5k2/zanV/TNQDGFVKBqtAlw+HvirHj/uMp d91WfBmdnK/WGSzwfj9bbIFA8YG7exOEDBBJIYKziaiVmqXfy6uW58J4U1mEdZ6cPcx9 zCKOl67So2udYcFODqgJJEv9MO4J3KaYO79LqitpcKL33PYcTPjWSHlJEzi07OQNAaUf xhWjSfzO7+ZCa8dZf7NCr+b1lxh2SlD5kLGcHSO7u3CQyKCEDvHbC8G52l9kYUk/J8y+ Q8qg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Pwl3VRG7l199xZxXoBkdQ57y28gQcRR32eC7hYs9l4c=; b=BNkEmRzW0BxjR7WttBe8IrBTK1crOFZ4D/GFCp+83AxHYcSboSil8uM/udVlc0BnZu XAWvdvkV58pFmB6GaXB3eEv7bRqCHqZ3tlgZC7H8HpVhkX8LJiLmmfTq90EeuCo/SMta eF6N58/QBZF5ox1MIHZ4luN908F53/xHq2xKxoWtDyJJngXid7kIllq9JJPWihhZ1QB0 GrBlkz6i3va8AUxyATCY1I+nyU3gT8PrJ5sgxd1zyNVNiKfehPDxmWUDYLLBBZQZKnPb ZeS26gvXeuH1HJpFFdk8o14FzPoKHOWXZL4Rp8iwlLOCcYPQLch5gVXGF1e0aJ/ywRBB 10iQ== X-Gm-Message-State: ANhLgQ0N36fNsozz5KZHufHizfabmUVB9/SwZHHD6KA3xH5Z8waMMI8E PcG+Dd2AOE0LtIT2tM1ittYGE9+Xnzh0nJ+A X-Google-Smtp-Source: ADFU+vsYnWygxaZdLWxuwiGudbZrcGJUrSwc+9kGKeC9fi4pOh1OgxeTaEDnXEJ7XF0KIUsfQI7FXPCAd+OsDFL1 X-Received: by 2002:adf:b31d:: with SMTP id j29mr5068188wrd.218.1584655926761; Thu, 19 Mar 2020 15:12:06 -0700 (PDT) Date: Thu, 19 Mar 2020 23:11:39 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v3 5/7] kcov: use t->kcov_mode as enabled indicator From: Andrey Konovalov To: Dmitry Vyukov Cc: Greg Kroah-Hartman , Alan Stern , Andrew Morton , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Potapenko , Marco Elver , Andrey Konovalov , Andrey Konovalov Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Andrey Konovalov Currently kcov_remote_start() and kcov_remote_stop() check t->kcov to find out whether the coverage is already being collected by the current task. Use t->kcov_mode for that instead. This doesn't change the overall behavior in any way, but serves as a preparation for the following softirq coverage collection support patch. Signed-off-by: Andrey Konovalov --- kernel/kcov.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index b985b7a72870..e43f06b5b2e4 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -746,26 +746,33 @@ static const struct file_operations kcov_fops = { * In turns kcov_remote_stop() clears those pointers from task_struct to stop * collecting coverage and copies all collected coverage into the kcov area. */ + +static inline bool kcov_mode_enabled(unsigned int mode) +{ + return (mode & ~KCOV_IN_CTXSW) != KCOV_MODE_DISABLED; +} + void kcov_remote_start(u64 handle) { + struct task_struct *t = current; struct kcov_remote *remote; struct kcov *kcov; + unsigned int mode; void *area; - struct task_struct *t; unsigned int size; - enum kcov_mode mode; int sequence; if (WARN_ON(!kcov_check_handle(handle, true, true, true))) return; if (WARN_ON(!in_task())) return; - t = current; + /* * Check that kcov_remote_start is not called twice * nor called by user tasks (with enabled kcov). */ - if (WARN_ON(t->kcov)) + mode = READ_ONCE(t->kcov_mode); + if (WARN_ON(kcov_mode_enabled(mode))) return; kcov_debug("handle = %llx\n", handle); @@ -863,13 +870,20 @@ static void kcov_move_area(enum kcov_mode mode, void *dst_area, void kcov_remote_stop(void) { struct task_struct *t = current; - struct kcov *kcov = t->kcov; - void *area = t->kcov_area; - unsigned int size = t->kcov_size; - int sequence = t->kcov_sequence; + struct kcov *kcov; + unsigned int mode; + void *area; + unsigned int size; + int sequence; - if (!kcov) + mode = READ_ONCE(t->kcov_mode); + barrier(); + if (!kcov_mode_enabled(mode)) return; + kcov = t->kcov; + area = t->kcov_area; + size = t->kcov_size; + sequence = t->kcov_sequence; kcov_stop(t); From patchwork Thu Mar 19 22:11:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11448143 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0351814B4 for ; Thu, 19 Mar 2020 22:12:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF23B207FC for ; Thu, 19 Mar 2020 22:12:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Wa4zjhYY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727534AbgCSWMO (ORCPT ); Thu, 19 Mar 2020 18:12:14 -0400 Received: from mail-wr1-f74.google.com ([209.85.221.74]:53221 "EHLO mail-wr1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727486AbgCSWMM (ORCPT ); Thu, 19 Mar 2020 18:12:12 -0400 Received: by mail-wr1-f74.google.com with SMTP id d17so1671856wrw.19 for ; Thu, 19 Mar 2020 15:12:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=8LGf7mqyvLqXZrrvJsz8LQcDGg59iY7bK5qVK/N9es0=; b=Wa4zjhYYw9fOnQZ803gTUAiJjoEKKYG8Xo5Xn8641bgx1vfOMqwEET8E9e6ZWYRUG/ BWUTYcpFSP/Yc/iR2fryFH3A8kjgIKBr0wn7s6GRaMfjar7fIk0jqJKyPOJK+2EqumKC RkeEeyd2byoXL3Qf3ShNq9VhebTgoA8eG3ZvQaUw9OHs3MfVfxV9UvrvnJeiS4cQ0Axd mn4c30uz9LPXLu/UOeKVYPG6qbmdpvrHBJDchPIUiDoWG+VGwJd5JnnDHczPFD/O0lXI YOIH3dAwGHfAPaZi8YqB+uiqZWUazpI6v1zdmamtSe6xECmzW3XDPkkYOj/vaOkavX1j tvTQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=8LGf7mqyvLqXZrrvJsz8LQcDGg59iY7bK5qVK/N9es0=; b=omxP4NfIMBhcbwntWvgsyTYNzX2TnXVvswccw8DuyY/z2lA7VxoL/m5vVboWytRwoI l+toSBEuePNfMPBqxc+BsYS7n8xyKIPIJadMrofbv+GPmtvBiW/5Olhs37FDqOTDHEO+ KvF4JuwbgdooqGzZboeLgsvIs7JjJSiTQgpKUdbNLFI0LneozzjGGf2TLA2C70vPMGBY cMGXbLgmNpIuWTwDgvjPcO3rfrm0JAQvZ2LjHnvToLGTcxUbQWaGJAuYWhtfxLmfQ6lm 9noMlMMBbHeW3z3oEfRGApyRw48d9TKaK3Q1Nb4ejJANtUvGXGZURCNO2w7Qzd4tGUuA 1URA== X-Gm-Message-State: ANhLgQ1tPTwVDtRtp1NwpVBsex9enGanM5wJvx6r9kic0Xnp5CRaRQfS P6vyNf0lhnWmJbknWYUG0CU4zCWQc7PwYf/w X-Google-Smtp-Source: ADFU+vuFyA/Xz/jPv5nBTJW3XDTUs7apjv2wzeBcU9KexYm5pCPMedFFcUJhm/SRQ1qE5C/o+VfNUOh1BYaJyEGE X-Received: by 2002:adf:ec82:: with SMTP id z2mr7178209wrn.302.1584655930071; Thu, 19 Mar 2020 15:12:10 -0700 (PDT) Date: Thu, 19 Mar 2020 23:11:40 +0100 In-Reply-To: Message-Id: <469bd385c431d050bc38a593296eff4baae50666.1584655448.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v3 6/7] kcov: collect coverage from interrupts From: Andrey Konovalov To: Dmitry Vyukov Cc: Greg Kroah-Hartman , Alan Stern , Andrew Morton , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Potapenko , Marco Elver , Andrey Konovalov Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org This change extends kcov remote coverage support to allow collecting coverage from soft interrupts in addition to kernel background threads. To collect coverage from code that is executed in softirq context, a part of that code has to be annotated with kcov_remote_start/stop() in a similar way as how it is done for global kernel background threads. Then the handle used for the annotations has to be passed to the KCOV_REMOTE_ENABLE ioctl. Internally this patch adjusts the __sanitizer_cov_trace_pc() compiler inserted callback to not bail out when called from softirq context. kcov_remote_start/stop() are updated to save/restore the current per task kcov state in a per-cpu area (in case the softirq came when the kernel was already collecting coverage in task context). Coverage from softirqs is collected into pre-allocated per-cpu areas, whose size is controlled by the new CONFIG_KCOV_IRQ_AREA_SIZE. Signed-off-by: Andrey Konovalov --- Documentation/dev-tools/kcov.rst | 17 +-- include/linux/sched.h | 3 + kernel/kcov.c | 194 ++++++++++++++++++++++++------- lib/Kconfig.debug | 9 ++ 4 files changed, 176 insertions(+), 47 deletions(-) diff --git a/Documentation/dev-tools/kcov.rst b/Documentation/dev-tools/kcov.rst index 1c4e1825d769..8548b0b04e43 100644 --- a/Documentation/dev-tools/kcov.rst +++ b/Documentation/dev-tools/kcov.rst @@ -217,14 +217,15 @@ This allows to collect coverage from two types of kernel background threads: the global ones, that are spawned during kernel boot in a limited number of instances (e.g. one USB hub_event() worker thread is spawned per USB HCD); and the local ones, that are spawned when a user interacts with -some kernel interface (e.g. vhost workers). +some kernel interface (e.g. vhost workers); as well as from soft +interrupts. -To enable collecting coverage from a global background thread, a unique -global handle must be assigned and passed to the corresponding -kcov_remote_start() call. Then a userspace process can pass a list of such -handles to the KCOV_REMOTE_ENABLE ioctl in the handles array field of the -kcov_remote_arg struct. This will attach the used kcov device to the code -sections, that are referenced by those handles. +To enable collecting coverage from a global background thread or from a +softirq, a unique global handle must be assigned and passed to the +corresponding kcov_remote_start() call. Then a userspace process can pass +a list of such handles to the KCOV_REMOTE_ENABLE ioctl in the handles +array field of the kcov_remote_arg struct. This will attach the used kcov +device to the code sections, that are referenced by those handles. Since there might be many local background threads spawned from different userspace processes, we can't use a single global handle per annotation. @@ -242,7 +243,7 @@ handles as they don't belong to a particular subsystem. The bytes 4-7 are currently reserved and must be zero. In the future the number of bytes used for the subsystem or handle ids might be increased. -When a particular userspace proccess collects coverage by via a common +When a particular userspace proccess collects coverage via a common handle, kcov will collect coverage for each code section that is annotated to use the common handle obtained as kcov_handle from the current task_struct. However non common handles allow to collect coverage diff --git a/include/linux/sched.h b/include/linux/sched.h index 04278493bf15..ce47d685fa55 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1229,6 +1229,9 @@ struct task_struct { /* KCOV sequence number: */ int kcov_sequence; + + /* Collect coverage from softirq context: */ + bool kcov_softirq; #endif #ifdef CONFIG_MEMCG diff --git a/kernel/kcov.c b/kernel/kcov.c index e43f06b5b2e4..50d330a2b30d 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -86,6 +86,18 @@ static DEFINE_SPINLOCK(kcov_remote_lock); static DEFINE_HASHTABLE(kcov_remote_map, 4); static struct list_head kcov_remote_areas = LIST_HEAD_INIT(kcov_remote_areas); +struct kcov_percpu_data { + void *irq_area; + + unsigned int saved_mode; + unsigned int saved_size; + void *saved_area; + struct kcov *saved_kcov; + int saved_sequence; +}; + +DEFINE_PER_CPU(struct kcov_percpu_data, kcov_percpu_data); + /* Must be called with kcov_remote_lock locked. */ static struct kcov_remote *kcov_remote_find(u64 handle) { @@ -145,9 +157,10 @@ static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_stru /* * We are interested in code coverage as a function of a syscall inputs, - * so we ignore code executed in interrupts. + * so we ignore code executed in interrupts, unless we are in a remote + * coverage collection section in a softirq. */ - if (!in_task()) + if (!in_task() && !(in_serving_softirq() && t->kcov_softirq)) return false; mode = READ_ONCE(t->kcov_mode); /* @@ -360,8 +373,9 @@ static void kcov_remote_reset(struct kcov *kcov) int bkt; struct kcov_remote *remote; struct hlist_node *tmp; + unsigned long flags; - spin_lock(&kcov_remote_lock); + spin_lock_irqsave(&kcov_remote_lock, flags); hash_for_each_safe(kcov_remote_map, bkt, tmp, remote, hnode) { if (remote->kcov != kcov) continue; @@ -370,7 +384,7 @@ static void kcov_remote_reset(struct kcov *kcov) } /* Do reset before unlock to prevent races with kcov_remote_start(). */ kcov_reset(kcov); - spin_unlock(&kcov_remote_lock); + spin_unlock_irqrestore(&kcov_remote_lock, flags); } static void kcov_disable(struct task_struct *t, struct kcov *kcov) @@ -399,12 +413,13 @@ static void kcov_put(struct kcov *kcov) void kcov_task_exit(struct task_struct *t) { struct kcov *kcov; + unsigned long flags; kcov = t->kcov; if (kcov == NULL) return; - spin_lock(&kcov->lock); + spin_lock_irqsave(&kcov->lock, flags); kcov_debug("t = %px, kcov->t = %px\n", t, kcov->t); /* * For KCOV_ENABLE devices we want to make sure that t->kcov->t == t, @@ -428,12 +443,12 @@ void kcov_task_exit(struct task_struct *t) * By combining all three checks into one we get: */ if (WARN_ON(kcov->t != t)) { - spin_unlock(&kcov->lock); + spin_unlock_irqrestore(&kcov->lock, flags); return; } /* Just to not leave dangling references behind. */ kcov_disable(t, kcov); - spin_unlock(&kcov->lock); + spin_unlock_irqrestore(&kcov->lock, flags); kcov_put(kcov); } @@ -444,12 +459,13 @@ static int kcov_mmap(struct file *filep, struct vm_area_struct *vma) struct kcov *kcov = vma->vm_file->private_data; unsigned long size, off; struct page *page; + unsigned long flags; area = vmalloc_user(vma->vm_end - vma->vm_start); if (!area) return -ENOMEM; - spin_lock(&kcov->lock); + spin_lock_irqsave(&kcov->lock, flags); size = kcov->size * sizeof(unsigned long); if (kcov->mode != KCOV_MODE_INIT || vma->vm_pgoff != 0 || vma->vm_end - vma->vm_start != size) { @@ -459,7 +475,7 @@ static int kcov_mmap(struct file *filep, struct vm_area_struct *vma) if (!kcov->area) { kcov->area = area; vma->vm_flags |= VM_DONTEXPAND; - spin_unlock(&kcov->lock); + spin_unlock_irqrestore(&kcov->lock, flags); for (off = 0; off < size; off += PAGE_SIZE) { page = vmalloc_to_page(kcov->area + off); if (vm_insert_page(vma, vma->vm_start + off, page)) @@ -468,7 +484,7 @@ static int kcov_mmap(struct file *filep, struct vm_area_struct *vma) return 0; } exit: - spin_unlock(&kcov->lock); + spin_unlock_irqrestore(&kcov->lock, flags); vfree(area); return res; } @@ -548,6 +564,7 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, int mode, i; struct kcov_remote_arg *remote_arg; struct kcov_remote *remote; + unsigned long flags; switch (cmd) { case KCOV_INIT_TRACE: @@ -620,17 +637,19 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, kcov->t = t; kcov->remote = true; kcov->remote_size = remote_arg->area_size; - spin_lock(&kcov_remote_lock); + spin_lock_irqsave(&kcov_remote_lock, flags); for (i = 0; i < remote_arg->num_handles; i++) { if (!kcov_check_handle(remote_arg->handles[i], false, true, false)) { - spin_unlock(&kcov_remote_lock); + spin_unlock_irqrestore(&kcov_remote_lock, + flags); kcov_disable(t, kcov); return -EINVAL; } remote = kcov_remote_add(kcov, remote_arg->handles[i]); if (IS_ERR(remote)) { - spin_unlock(&kcov_remote_lock); + spin_unlock_irqrestore(&kcov_remote_lock, + flags); kcov_disable(t, kcov); return PTR_ERR(remote); } @@ -638,20 +657,22 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, if (remote_arg->common_handle) { if (!kcov_check_handle(remote_arg->common_handle, true, false, false)) { - spin_unlock(&kcov_remote_lock); + spin_unlock_irqrestore(&kcov_remote_lock, + flags); kcov_disable(t, kcov); return -EINVAL; } remote = kcov_remote_add(kcov, remote_arg->common_handle); if (IS_ERR(remote)) { - spin_unlock(&kcov_remote_lock); + spin_unlock_irqrestore(&kcov_remote_lock, + flags); kcov_disable(t, kcov); return PTR_ERR(remote); } t->kcov_handle = remote_arg->common_handle; } - spin_unlock(&kcov_remote_lock); + spin_unlock_irqrestore(&kcov_remote_lock, flags); /* Put either in kcov_task_exit() or in KCOV_DISABLE. */ kcov_get(kcov); return 0; @@ -667,6 +688,7 @@ static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) struct kcov_remote_arg *remote_arg = NULL; unsigned int remote_num_handles; unsigned long remote_arg_size; + unsigned long flags; if (cmd == KCOV_REMOTE_ENABLE) { if (get_user(remote_num_handles, (unsigned __user *)(arg + @@ -687,9 +709,9 @@ static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) } kcov = filep->private_data; - spin_lock(&kcov->lock); + spin_lock_irqsave(&kcov->lock, flags); res = kcov_ioctl_locked(kcov, cmd, arg); - spin_unlock(&kcov->lock); + spin_unlock_irqrestore(&kcov->lock, flags); kfree(remote_arg); @@ -706,8 +728,8 @@ static const struct file_operations kcov_fops = { /* * kcov_remote_start() and kcov_remote_stop() can be used to annotate a section - * of code in a kernel background thread to allow kcov to be used to collect - * coverage from that part of code. + * of code in a kernel background thread or in a softirq to allow kcov to be + * used to collect coverage from that part of code. * * The handle argument of kcov_remote_start() identifies a code section that is * used for coverage collection. A userspace process passes this handle to @@ -718,9 +740,9 @@ static const struct file_operations kcov_fops = { * the type of the kernel thread whose code is being annotated. * * For global kernel threads that are spawned in a limited number of instances - * (e.g. one USB hub_event() worker thread is spawned per USB HCD), each - * instance must be assigned a unique 4-byte instance id. The instance id is - * then combined with a 1-byte subsystem id to get a handle via + * (e.g. one USB hub_event() worker thread is spawned per USB HCD) and for + * softirqs, each instance must be assigned a unique 4-byte instance id. The + * instance id is then combined with a 1-byte subsystem id to get a handle via * kcov_remote_handle(subsystem_id, instance_id). * * For local kernel threads that are spawned from system calls handler when a @@ -739,7 +761,7 @@ static const struct file_operations kcov_fops = { * * See Documentation/dev-tools/kcov.rst for more details. * - * Internally, this function looks up the kcov device associated with the + * Internally, kcov_remote_start() looks up the kcov device associated with the * provided handle, allocates an area for coverage collection, and saves the * pointers to kcov and area into the current task_struct to allow coverage to * be collected via __sanitizer_cov_trace_pc() @@ -752,6 +774,39 @@ static inline bool kcov_mode_enabled(unsigned int mode) return (mode & ~KCOV_IN_CTXSW) != KCOV_MODE_DISABLED; } +void kcov_remote_softirq_start(struct task_struct *t) +{ + struct kcov_percpu_data *data = this_cpu_ptr(&kcov_percpu_data); + unsigned int mode; + + mode = READ_ONCE(t->kcov_mode); + barrier(); + if (kcov_mode_enabled(mode)) { + data->saved_mode = mode; + data->saved_size = t->kcov_size; + data->saved_area = t->kcov_area; + data->saved_sequence = t->kcov_sequence; + data->saved_kcov = t->kcov; + kcov_stop(t); + } +} + +void kcov_remote_softirq_stop(struct task_struct *t) +{ + struct kcov_percpu_data *data = this_cpu_ptr(&kcov_percpu_data); + + if (data->saved_kcov) { + kcov_start(t, data->saved_kcov, data->saved_size, + data->saved_area, data->saved_mode, + data->saved_sequence); + data->saved_mode = 0; + data->saved_size = 0; + data->saved_area = NULL; + data->saved_sequence = 0; + data->saved_kcov = NULL; + } +} + void kcov_remote_start(u64 handle) { struct task_struct *t = current; @@ -761,28 +816,42 @@ void kcov_remote_start(u64 handle) void *area; unsigned int size; int sequence; + unsigned long flags; if (WARN_ON(!kcov_check_handle(handle, true, true, true))) return; - if (WARN_ON(!in_task())) + if (!in_task() && !in_serving_softirq()) return; + local_irq_save(flags); + /* - * Check that kcov_remote_start is not called twice - * nor called by user tasks (with enabled kcov). + * Check that kcov_remote_start() is not called twice in background + * threads nor called by user tasks (with enabled kcov). */ mode = READ_ONCE(t->kcov_mode); - if (WARN_ON(kcov_mode_enabled(mode))) + if (WARN_ON(in_task() && kcov_mode_enabled(mode))) { + local_irq_restore(flags); return; - - kcov_debug("handle = %llx\n", handle); + } + /* + * Check that kcov_remote_start() is not called twice in softirqs. + * Note, that kcov_remote_start() can be called from a softirq that + * happened while collecting coverage from a background thread. + */ + if (WARN_ON(in_serving_softirq() && t->kcov_softirq)) { + local_irq_restore(flags); + return; + } spin_lock(&kcov_remote_lock); remote = kcov_remote_find(handle); if (!remote) { - spin_unlock(&kcov_remote_lock); + spin_unlock_irqrestore(&kcov_remote_lock, flags); return; } + kcov_debug("handle = %llx, context: %s\n", handle, + in_task() ? "task" : "softirq"); kcov = remote->kcov; /* Put in kcov_remote_stop(). */ kcov_get(kcov); @@ -790,12 +859,18 @@ void kcov_remote_start(u64 handle) * Read kcov fields before unlock to prevent races with * KCOV_DISABLE / kcov_remote_reset(). */ - size = kcov->remote_size; mode = kcov->mode; sequence = kcov->sequence; - area = kcov_remote_area_get(size); - spin_unlock(&kcov_remote_lock); + if (in_task()) { + size = kcov->remote_size; + area = kcov_remote_area_get(size); + } else { + size = CONFIG_KCOV_IRQ_AREA_SIZE; + area = this_cpu_ptr(&kcov_percpu_data)->irq_area; + } + spin_unlock_irqrestore(&kcov_remote_lock, flags); + /* Can only happen when in_task(). */ if (!area) { area = vmalloc(size * sizeof(unsigned long)); if (!area) { @@ -803,11 +878,20 @@ void kcov_remote_start(u64 handle) return; } } + + local_irq_save(flags); + /* Reset coverage size. */ *(u64 *)area = 0; + if (in_serving_softirq()) { + kcov_remote_softirq_start(t); + t->kcov_softirq = true; + } kcov_start(t, kcov, size, area, mode, sequence); + local_irq_restore(flags); + } EXPORT_SYMBOL(kcov_remote_start); @@ -875,31 +959,53 @@ void kcov_remote_stop(void) void *area; unsigned int size; int sequence; + unsigned long flags; + + if (!in_task() && !in_serving_softirq()) + return; + + local_irq_save(flags); mode = READ_ONCE(t->kcov_mode); barrier(); - if (!kcov_mode_enabled(mode)) + if (!kcov_mode_enabled(mode)) { + local_irq_restore(flags); return; + } kcov = t->kcov; area = t->kcov_area; size = t->kcov_size; sequence = t->kcov_sequence; + if (WARN_ON(!in_serving_softirq() && t->kcov_softirq)) { + local_irq_restore(flags); + return; + } + kcov_stop(t); + if (in_serving_softirq()) { + t->kcov_softirq = false; + kcov_remote_softirq_stop(t); + } spin_lock(&kcov->lock); /* * KCOV_DISABLE could have been called between kcov_remote_start() - * and kcov_remote_stop(), hence the check. + * and kcov_remote_stop(), hence the sequence check. */ if (sequence == kcov->sequence && kcov->remote) kcov_move_area(kcov->mode, kcov->area, kcov->size, area); spin_unlock(&kcov->lock); - spin_lock(&kcov_remote_lock); - kcov_remote_area_put(area, size); - spin_unlock(&kcov_remote_lock); + if (in_task()) { + spin_lock(&kcov_remote_lock); + kcov_remote_area_put(area, size); + spin_unlock(&kcov_remote_lock); + } + local_irq_restore(flags); + + /* Get in kcov_remote_start(). */ kcov_put(kcov); } EXPORT_SYMBOL(kcov_remote_stop); @@ -913,6 +1019,16 @@ EXPORT_SYMBOL(kcov_common_handle); static int __init kcov_init(void) { + int cpu; + + for_each_possible_cpu(cpu) { + void *area = vmalloc(CONFIG_KCOV_IRQ_AREA_SIZE * + sizeof(unsigned long)); + if (!area) + return -ENOMEM; + per_cpu_ptr(&kcov_percpu_data, cpu)->irq_area = area; + } + /* * The kcov debugfs file won't ever get removed and thus, * there is no need to protect it against removal races. The diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 69def4a9df00..a1f25b27d32d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1740,6 +1740,15 @@ config KCOV_INSTRUMENT_ALL filesystem fuzzing with AFL) then you will want to enable coverage for more specific subsets of files, and should say n here. +config KCOV_IRQ_AREA_SIZE + hex "Size of interrupt coverage collection area in words" + depends on KCOV + default 0x40000 + help + KCOV uses preallocated per-cpu areas to collect coverage from + soft interrupts. This specifies the size of those areas in the + number of unsigned long words. + menuconfig RUNTIME_TESTING_MENU bool "Runtime Testing" def_bool y From patchwork Thu Mar 19 22:11:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11448145 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0985514B4 for ; Thu, 19 Mar 2020 22:12:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC4D7208D6 for ; Thu, 19 Mar 2020 22:12:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="wGNCWsxx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727486AbgCSWMQ (ORCPT ); Thu, 19 Mar 2020 18:12:16 -0400 Received: from mail-wr1-f73.google.com ([209.85.221.73]:38027 "EHLO mail-wr1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727477AbgCSWMP (ORCPT ); Thu, 19 Mar 2020 18:12:15 -0400 Received: by mail-wr1-f73.google.com with SMTP id q18so1682058wrw.5 for ; Thu, 19 Mar 2020 15:12:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Ec1QNNZB9RdZOPOOrrZEv520YKl8QD3P6+7VUng4a2o=; b=wGNCWsxxzE05P/opJCYnv1N8zFwNt6cTq4ckyZiz9oQ5890qOacNIWKpN7Y++MLt6+ +YKxBiZXwSFk1IGTSnQFc06R14nY8UWmBgLdcbf7MdFyRG1MvL6T6rd8RP3yB53TVKyf +Uc3R9oxRBqgWKVz/QSvUAel4ej1J8si1HLNu0Rai083j03ODYzNjaVZf5T0XtF/kjJh LwTg7zhgbj4V9RDUcQo4mmHihgfAC9ymlc6F/1mRhJPaKXIcT7VSTgKS++nhSDDRJStp Lp/miL7zNG4MdaM7dB/m1BK/l18wytSw5UL2GhIyw3LNguhr0wHydS463Cf5gI+Zqiwl CXqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Ec1QNNZB9RdZOPOOrrZEv520YKl8QD3P6+7VUng4a2o=; b=ILPLwcfBYnzt7jG/kxM93ejctXpCKmqOG/aD1v3Ntme0Ad6JUuLvTKTOe2cSVDIv/f SdqEkQwodAvSSn2ij6OJa09Tjf4EPa8vqmKfLvajz/lV43oXDzHX3SFiatVbcaKcVnr+ 0sdjdYbTCfimx098kcZlV/rLiNizbixC1Kvbd09uogNWRVdI6PzlJSEMYPg9ms4227GG XP0eQ/dutAsHWvvd6buK9Z20EWvkYAOc4roe14t6cg/HiLV9/gwQWidaDC5pvkqx43xs Vfl8jFWcBJvd1B4hT1nTCp26EqpmE2JZDJdnCrJxUX5P95JCRNoQ1HJdxGthNuvzJXvO C8nQ== X-Gm-Message-State: ANhLgQ08bB9xzpRiCn8LrmFNdeP8Xte4uN7vUkY7Ay+U3b4b8jd3EtkI 0GhN28KSnUULLwwkzX95PovhonKOWhypV4Jh X-Google-Smtp-Source: ADFU+vushxI8BnYkgZABMFdSfaL5+yV3YI3la2gcdZ5v3T5GugDgvBJQPNjSNj8fkPYEaoYtd6RE48XYpmoP4A7m X-Received: by 2002:adf:fe4c:: with SMTP id m12mr6989126wrs.96.1584655933185; Thu, 19 Mar 2020 15:12:13 -0700 (PDT) Date: Thu, 19 Mar 2020 23:11:41 +0100 In-Reply-To: Message-Id: <2821d497ac1cdc0efb5e00df30271e4a67fc8009.1584655448.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v3 7/7] usb: core: kcov: collect coverage from usb complete callback From: Andrey Konovalov To: Dmitry Vyukov Cc: Greg Kroah-Hartman , Alan Stern , Andrew Morton , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Potapenko , Marco Elver , Andrey Konovalov Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org This patch adds kcov_remote_start/stop() callbacks around the urb complete() callback that is executed in softirq context when dummy_hcd is in use. As the result, kcov can be used to collect coverage from those callbacks, which is used to facilitate coverage-guided fuzzing with syzkaller. Signed-off-by: Andrey Konovalov --- drivers/usb/core/hcd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index aa45840d8273..de624c47e190 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include @@ -1645,7 +1646,9 @@ static void __usb_hcd_giveback_urb(struct urb *urb) /* pass ownership to the completion handler */ urb->status = status; + kcov_remote_start_usb((u64)urb->dev->bus->busnum); urb->complete(urb); + kcov_remote_stop(); usb_anchor_resume_wakeups(anchor); atomic_dec(&urb->use_count);