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 2A7DD304BCA; Wed, 27 Aug 2025 20:24:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326263; cv=none; b=nG7RLxE01iWFoKd05O5sDb6D476wKIJDVwfnRxoQ1skon3o8GZsFhJMayH0OlC8eiRUBnxURNEaWgGqr6Qs6vpwfH5feiP6lK5NKJ0mQ8J1eDtnRqdepmkSfScLk3ITxop7Pumq3sXqAbRbzeZk8CEm+SR26DGkP7YjfDg+CTHE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326263; c=relaxed/simple; bh=B0Z0hge9MApW75b17usDdRxmkX5DdtylXDH/jRh6dj4=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=XP6RvX0mZOd/PRqlDUB1qxJ90VgOyBc/th99xOpVOi6JtdAv87GMwdpSDSLwH4BamNGQSkavMhgQ+qSXfWSWSb15IUbgpqce+ZCFi9bZHBpwitwlcPafGGj+4hsj7Usg9Dgo9RbuIxZrIqQmJV3Upu6HKus+PY5aajhBp5CUCio= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZN3lC9as; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZN3lC9as" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 056A3C4CEEB; Wed, 27 Aug 2025 20:24:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756326263; bh=B0Z0hge9MApW75b17usDdRxmkX5DdtylXDH/jRh6dj4=; h=Date:From:To:Cc:Subject:References:From; b=ZN3lC9as6z85Vu96b7dlCuCAB68Zp7ESIARXwCw6Qk6Egz6iQngzm/NVUtj9oiw+3 gcJumShNdJqQe11PveT1f2+ySFHwh7Y5+ma/HYdCIa/ii6zvN3+JaY/t1utHDCQKe3 SZU+ndOIQHieK6fIV7riyaEduBWJn4wpmx4ghCyX+GhqkuNJJbKA1tL4OFLTLVLqSv uQq2CFUgaVlgYKZfk3/6lEtKw8lO6hrVWIRIILBWjgiMtfFuLwYEaGDFzsthBBh7zy qHke4zqDC1XCgt+Nne0U1MnQc40HHb9ZykLKVDZxt8c2XRil2dW/Tvq9JiG/ykPVAo w4YN0JySoTXHA== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1urMhF-00000003l0o-3tCK; Wed, 27 Aug 2025 16:24:41 -0400 Message-ID: <20250827202441.776912299@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:58 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 10/11] unwind_user/sframe: Add .sframe validation option References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Josh Poimboeuf Add a debug feature to validate all .sframe sections when first loading the file rather than on demand. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- arch/Kconfig | 19 +++++++++ kernel/unwind/sframe.c | 96 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 115 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 277b87af949f..918ebe3c5a85 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -455,6 +455,25 @@ config HAVE_UNWIND_USER_SFRAME bool select UNWIND_USER +config SFRAME_VALIDATION + bool "Enable .sframe section debugging" + depends on HAVE_UNWIND_USER_SFRAME + depends on DYNAMIC_DEBUG + help + When adding an .sframe section for a task, validate the entire + section immediately rather than on demand. + + This is a debug feature which is helpful for rooting out .sframe + section issues. If the .sframe section is corrupt, it will fail to + load immediately, with more information provided in dynamic printks. + + This has a significant page cache footprint due to its reading of the + entire .sframe section for every loaded executable and shared + library. Also, it's done for all processes, even those which don't + get stack traced by the kernel. Not recommended for general use. + + If unsure, say N. + config HAVE_PERF_REGS bool help diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index 66d3ba3c8389..79ff3c0fc11f 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -319,6 +319,98 @@ int sframe_find(unsigned long ip, struct unwind_user_frame *frame) return ret; } +#ifdef CONFIG_SFRAME_VALIDATION + +static int safe_read_fde(struct sframe_section *sec, + unsigned int fde_num, struct sframe_fde *fde) +{ + int ret; + + if (!user_read_access_begin((void __user *)sec->sframe_start, + sec->sframe_end - sec->sframe_start)) + return -EFAULT; + ret = __read_fde(sec, fde_num, fde); + user_read_access_end(); + return ret; +} + +static int safe_read_fre(struct sframe_section *sec, + struct sframe_fde *fde, unsigned long fre_addr, + struct sframe_fre *fre) +{ + int ret; + + if (!user_read_access_begin((void __user *)sec->sframe_start, + sec->sframe_end - sec->sframe_start)) + return -EFAULT; + ret = __read_fre(sec, fde, fre_addr, fre); + user_read_access_end(); + return ret; +} + +static int sframe_validate_section(struct sframe_section *sec) +{ + unsigned long prev_ip = 0; + unsigned int i; + + for (i = 0; i < sec->num_fdes; i++) { + struct sframe_fre *fre, *prev_fre = NULL; + unsigned long ip, fre_addr; + struct sframe_fde fde; + struct sframe_fre fres[2]; + bool which = false; + unsigned int j; + int ret; + + ret = safe_read_fde(sec, i, &fde); + if (ret) + return ret; + + ip = sec->sframe_start + fde.start_addr; + if (ip <= prev_ip) { + dbg_sec("fde %u not sorted\n", i); + return -EFAULT; + } + prev_ip = ip; + + fre_addr = sec->fres_start + fde.fres_off; + for (j = 0; j < fde.fres_num; j++) { + int ret; + + fre = which ? fres : fres + 1; + which = !which; + + ret = safe_read_fre(sec, &fde, fre_addr, fre); + if (ret) { + dbg_sec("fde %u: __read_fre(%u) failed\n", i, j); + dbg_sec("FDE: start_addr:0x%x func_size:0x%x fres_off:0x%x fres_num:%d info:%u rep_size:%u\n", + fde.start_addr, fde.func_size, + fde.fres_off, fde.fres_num, + fde.info, fde.rep_size); + return ret; + } + + fre_addr += fre->size; + + if (prev_fre && fre->ip_off <= prev_fre->ip_off) { + dbg_sec("fde %u: fre %u not sorted\n", i, j); + return -EFAULT; + } + + prev_fre = fre; + } + } + + return 0; +} + +#else /* !CONFIG_SFRAME_VALIDATION */ + +static int sframe_validate_section(struct sframe_section *sec) { return 0; } + +#endif /* !CONFIG_SFRAME_VALIDATION */ + + static void free_section(struct sframe_section *sec) { dbg_free(sec); @@ -427,6 +519,10 @@ int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, goto err_free; } + ret = sframe_validate_section(sec); + if (ret) + goto err_free; + ret = mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec, GFP_KERNEL); if (ret) { dbg_sec("mtree_insert_range failed: text=%lx-%lx\n", -- 2.50.1