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So lets merge fastrpc_map_find into fastrpc_map_lookup which allows us to both protect the maps list by also taking the &fl->lock spinlock and the reference count, since the spinlock will be released only after. Add take_ref argument to make this suitable for all callers. Fixes: 8f6c1d8c4f0c ("misc: fastrpc: Add fdlist implementation") Co-developed-by: Ola Jeppsson Signed-off-by: Ola Jeppsson Signed-off-by: Abel Vesa Signed-off-by: Srinivas Kandagatla --- drivers/misc/fastrpc.c | 41 +++++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 7ff0b63c25e3..fc2173c59f8b 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -333,30 +333,31 @@ static void fastrpc_map_get(struct fastrpc_map *map) static int fastrpc_map_lookup(struct fastrpc_user *fl, int fd, - struct fastrpc_map **ppmap) + struct fastrpc_map **ppmap, bool take_ref) { + struct fastrpc_session_ctx *sess = fl->sctx; struct fastrpc_map *map = NULL; + int ret = -ENOENT; - mutex_lock(&fl->mutex); + spin_lock(&fl->lock); list_for_each_entry(map, &fl->maps, node) { - if (map->fd == fd) { - *ppmap = map; - mutex_unlock(&fl->mutex); - return 0; - } - } - mutex_unlock(&fl->mutex); - - return -ENOENT; -} + if (map->fd != fd) + continue; -static int fastrpc_map_find(struct fastrpc_user *fl, int fd, - struct fastrpc_map **ppmap) -{ - int ret = fastrpc_map_lookup(fl, fd, ppmap); + if (take_ref) { + ret = fastrpc_map_get(map); + if (ret) { + dev_dbg(sess->dev, "%s: Failed to get map fd=%d ret=%d\n", + __func__, fd, ret); + break; + } + } - if (!ret) - fastrpc_map_get(*ppmap); + *ppmap = map; + ret = 0; + break; + } + spin_unlock(&fl->lock); return ret; } @@ -703,7 +704,7 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd, struct fastrpc_map *map = NULL; int err = 0; - if (!fastrpc_map_find(fl, fd, ppmap)) + if (!fastrpc_map_lookup(fl, fd, ppmap, true)) return 0; map = kzalloc(sizeof(*map), GFP_KERNEL); @@ -1026,7 +1027,7 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx, for (i = 0; i < FASTRPC_MAX_FDLIST; i++) { if (!fdlist[i]) break; - if (!fastrpc_map_lookup(fl, (int)fdlist[i], &mmap)) + if (!fastrpc_map_lookup(fl, (int)fdlist[i], &mmap, false)) fastrpc_map_put(mmap); } From patchwork Thu Nov 24 17:49:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Srinivas Kandagatla X-Patchwork-Id: 25659 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp3533945wrr; Thu, 24 Nov 2022 09:52:26 -0800 (PST) X-Google-Smtp-Source: AA0mqf7XCmSiVmCd0HSbvTQJUaw3GydL1SuppthU2TTrSVeVqPicJbLok8GBgWeVa2VKaHT+Vtde X-Received: by 2002:aa7:cf07:0:b0:469:5aae:5807 with SMTP id a7-20020aa7cf07000000b004695aae5807mr22487244edy.133.1669312346061; Thu, 24 Nov 2022 09:52:26 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1669312346; cv=none; d=google.com; s=arc-20160816; b=0itHgU0iJOQsIn1v/JQXtescj1CMCtdrZbWoSG75u05y5QEyL5XOf5fljHzFiSNJbJ 9XHF37508M8AK3qDp5EBeBQPiBlDFw3X3kv/TzHGajPEE6eC7PoNlXWrsVFGqtBV2JLv Oaj/S+AH3Z6veR9c8k3Chmk/b5WYL0/8JQzYdb6sXyy35ehrdmhXqWln2OXVcEHnatgq 6aLp0heYzEMyrWPMeWdJDZ4k1877472mN1irroOc4hygyfTmpjHgBceb/GakbOM5O/0+ 4CmlWjm87CtcWBXnUE1H9ZZ4SpmDrzJMi1hisfd5HvGxt9z141ZMHFSPrYn3DZjXXPG8 te4Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=WnrDbdRJkbksqZItXruR6kyL5+sqtubhQgH9dDxfehQ=; b=Kjl3gQS07KonB0XJqik+dQN8wsESwnAzNPipPX+pZf15sgJcXyEg/w2oke4n/vJbDc /Nvf/8fdIOSUPGX/QsUBVXsmK00sMy6r1jnibKozQ6ga0WoGhEgMC3YM5G95IC+sDuuX 2VUKAtRT9DoamLlGLw/pu0DS4zPfocn6+LgH0JK/vZu74NDyt5J+gnesaZ8hUYfA5v4G bbNlkUDzE+OVntgl7fdW8X4wgtTKudrcru/5RrpH8jrXijpRG8kosPAo4vp0u6F6Q/p9 /l84EQqct6DaKLdE6V2DChdp43MF0w6mYIO2mQCk83kchgF1sEf4JZ4fq9/mKQPSl9J/ wMBQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=xoMkl3Ee; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: from out1.vger.email (out1.vger.email. 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Do not remove it on fastrpc_device_release either, call fastrpc_map_put instead. The fastrpc_free_map is the only proper place to remove the map. This is called only after the reference count is 0. Fixes: b49f6d83e290 ("misc: fastrpc: Fix a possible double free") Co-developed-by: Ola Jeppsson Signed-off-by: Ola Jeppsson Signed-off-by: Abel Vesa Signed-off-by: Srinivas Kandagatla --- drivers/misc/fastrpc.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index fc2173c59f8b..9ecbf673d321 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -316,6 +316,13 @@ static void fastrpc_free_map(struct kref *ref) dma_buf_put(map->buf); } + if (map->fl) { + spin_lock(&map->fl->lock); + list_del(&map->node); + spin_unlock(&map->fl->lock); + map->fl = NULL; + } + kfree(map); } @@ -1266,12 +1273,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl, fl->init_mem = NULL; fastrpc_buf_free(imem); err_alloc: - if (map) { - spin_lock(&fl->lock); - list_del(&map->node); - spin_unlock(&fl->lock); - fastrpc_map_put(map); - } + fastrpc_map_put(map); err: kfree(args); @@ -1347,10 +1349,8 @@ static int fastrpc_device_release(struct inode *inode, struct file *file) fastrpc_context_put(ctx); } - list_for_each_entry_safe(map, m, &fl->maps, node) { - list_del(&map->node); + list_for_each_entry_safe(map, m, &fl->maps, node) fastrpc_map_put(map); - } list_for_each_entry_safe(buf, b, &fl->mmaps, node) { list_del(&buf->node); From patchwork Thu Nov 24 17:49:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Srinivas Kandagatla X-Patchwork-Id: 25660 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp3534055wrr; Thu, 24 Nov 2022 09:52:40 -0800 (PST) X-Google-Smtp-Source: AA0mqf5ETVcPcoM8609TV0SfFTXU4QCphAV7+Vf2ah/h3ZEO/4QEnJpEC9HfDgjloPWHb1qwGsvT X-Received: by 2002:a17:907:77d6:b0:78d:e26f:bfd8 with SMTP id kz22-20020a17090777d600b0078de26fbfd8mr28881427ejc.482.1669312360373; Thu, 24 Nov 2022 09:52:40 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1669312360; cv=none; d=google.com; s=arc-20160816; b=K2FUJP41Q8ecP0e8sJrIvov693FdxyCEw+wLFuXPeAGTtZPh9cXTGGKZX8XFRUu/Q/ cJJO7wbtOLcLj67PrqMVVl52BtdI3PIHn9AF86u8EqTgjr0s9yrXEiozaFepgHnUItpz w5cuVcbafCae9wEccJuLkBRdx55bdPMBHDEjfhdzutE0tHYdRKDmJih313ka357+u7Vy yMZ+cdgRuFYRp5gmUBprTl3KkPNKo7OVPPwLyYMbulFIei6AtBVZLSVmxq5rsEDIc6h4 5e3VyCkDw4J9ng/RjolOOOsmzdw+EcoNS5kbvLWM0pM/9hV4VGpN2XnLKooQmCoSkpHX XsmA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=/KFXcD5/aBYcFLibXAaTRcTYcuQsFKMCk/mHDgk2MPE=; b=ncxQTQLUEWZBSBEq0JsudzI5ViIW10YeT5up3Isu/Eu44NRSS0x5094kwM8ki3DtTq kBqOOcfe8cA9GC4WzNbyNWoAhLaaQpBPvVilzyF9HRijfHzh4AXkbWlaSuBSYoUjYgFJ u8uDA9eZgGnvyx6KGgeRV+dUsWFQGJkFAAct4CgOtj2wIEgT3JJTRtP3kYH1gfbDCi1j +qj4/wDvylEDpLhXl4jUeR5zBC3xVBf7UB3lpBe0/nYdnUiJdObcWbvzRF4UPNxtEjYU DbnC1cI1PBiuRuuruLbk7yV7msI43gfe0r6Nid9js8c7Dz2UcRzidWmnaVT+uA/VZVdv HUGw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=a7INjNtt; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: from out1.vger.email (out1.vger.email. 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Rewrite fastrpc_map_get() to only increase the reference count of a map if it's non-zero. Propagate this to callers so they can know if a map is about to be deleted. Fixes this warning: refcount_t: addition on 0; use-after-free. WARNING: CPU: 5 PID: 10100 at lib/refcount.c:25 refcount_warn_saturate ... Call trace: refcount_warn_saturate [fastrpc_map_get inlined] [fastrpc_map_lookup inlined] fastrpc_map_create fastrpc_internal_invoke fastrpc_device_ioctl __arm64_sys_ioctl invoke_syscall Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Signed-off-by: Ola Jeppsson Signed-off-by: Abel Vesa Signed-off-by: Srinivas Kandagatla --- drivers/misc/fastrpc.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 9ecbf673d321..80811e852d8f 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -332,10 +332,12 @@ static void fastrpc_map_put(struct fastrpc_map *map) kref_put(&map->refcount, fastrpc_free_map); } -static void fastrpc_map_get(struct fastrpc_map *map) +static int fastrpc_map_get(struct fastrpc_map *map) { - if (map) - kref_get(&map->refcount); + if (!map) + return -ENOENT; + + return kref_get_unless_zero(&map->refcount) ? 0 : -ENOENT; }