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 8DA4F7081D; Wed, 13 Nov 2024 22:21:01 +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=1731536461; cv=none; b=KuDKEx7rMiEMTLZxswdGhvVziw46KjzGfADkizFBgyKt2QY6TyGws674Y4LmCSNMpmLCl43VJCYeePZrqbFqNQAAjN1/OiXDdN6vU0LvF0hNMHoqzhT3LRyVxdGecUOYIOroj0mIGUMTFy8LpVE40ft0vtVaJVEqVnmgiysGa68= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731536461; c=relaxed/simple; bh=jaCgkVrjqdFRoXcmyT5u0vZq+LcNAv9DOc0Nl7LGbn4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Lg7CH3AkiFLqJo3tFon7jZaneULeoJhl/phjOc4nN/R/oZSmf4QI0MDkiAi2hDEuwgLkZIo6DfEvWxvSzIFUsK67ODFKTShgLJO4wxEW8W8gYdrxidv7gqiZ0Qj+NskuSh35MG69bwC63tknGpBL5BPIRkN8TEPm0DramOqlMfM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C89EC4CEC3; Wed, 13 Nov 2024 22:20:58 +0000 (UTC) Date: Wed, 13 Nov 2024 17:21:18 -0500 From: Steven Rostedt To: Josh Poimboeuf Cc: Jens Remus , x86@kernel.org, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Indu Bhagat , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , linux-perf-users@vger.kernel.org, Mark Brown , linux-toolchains@vger.kernel.org, Jordan Rome , Sam James , linux-trace-kernel@vger.kernel.org, Andrii Nakryiko , Mathieu Desnoyers , Florian Weimer , Andy Lutomirski , Heiko Carstens , Vasily Gorbik Subject: Re: [PATCH v3 09/19] unwind: Introduce sframe user space unwinding Message-ID: <20241113172118.6db57c42@gandalf.local.home> In-Reply-To: <20241113171326.6d1ddc83@gandalf.local.home> References: <42c0a99236af65c09c8182e260af7bcf5aa1e158.1730150953.git.jpoimboe@kernel.org> <1f83be89-b816-48a3-a7ee-9b72f07b558e@linux.ibm.com> <20241113155040.6a9a1bed@gandalf.local.home> <20241113211535.ghnw52wkgudkjvgv@jpoimboe> <20241113171326.6d1ddc83@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit [ This reply fixes the linux-trace-kernel email :-p ] On Wed, 13 Nov 2024 17:13:26 -0500 Steven Rostedt wrote: > BTW, the following changes were needed to make it work for me: > > -- Steve > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index 434c548f0837..64cc3c1188ca 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -842,7 +842,8 @@ static int load_elf_binary(struct linux_binprm *bprm) > int first_pt_load = 1; > unsigned long error; > struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL; > - struct elf_phdr *elf_property_phdata = NULL, *sframe_phdr = NULL; > + struct elf_phdr *elf_property_phdata = NULL; > + unsigned long sframe_vaddr = 0; Could not just save the pointer to the sframe phd, as it gets freed before we need it. > unsigned long elf_brk; > int retval, i; > unsigned long elf_entry; > @@ -951,7 +952,7 @@ static int load_elf_binary(struct linux_binprm *bprm) > break; > > case PT_GNU_SFRAME: > - sframe_phdr = elf_ppnt; > + sframe_vaddr = elf_ppnt->p_vaddr; > break; > > case PT_LOPROC ... PT_HIPROC: > @@ -1344,8 +1345,8 @@ static int load_elf_binary(struct linux_binprm *bprm) > task_pid_nr(current), retval); > } > > - if (sframe_phdr) > - sframe_add_section(load_bias + sframe_phdr->p_vaddr, > + if (sframe_vaddr) > + sframe_add_section(load_bias + sframe_vaddr, > start_code, end_code); > > regs = current_pt_regs(); > diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c > index 933e47696e29..ca4ef0b72772 100644 > --- a/kernel/unwind/sframe.c > +++ b/kernel/unwind/sframe.c > @@ -73,15 +73,15 @@ static int find_fde(struct sframe_section *sec, unsigned long ip, > struct sframe_fde *fde) > { > struct sframe_fde __user *first, *last, *found = NULL; > - u32 ip_off, func_off_low = 0, func_off_high = -1; > + s32 ip_off, func_off_low = INT_MIN, func_off_high = INT_MAX; The ip_off is a signed it. I wrote a program to dump out the sframe section of files, and I had: ffffed88: (1020) size: 16 off: 146 num: 2 info: 1 rep:16 ffffed98: (1030) size: 336 off: 154 num: 2 info:17 rep:16 ffffefe1: (1279) size: 113 off: 0 num: 4 info: 0 rep: 0 fffff052: (12ea) size: 54 off: 15 num: 3 info: 0 rep: 0 fffff088: (1320) size: 167 off: 26 num: 3 info: 0 rep: 0 fffff12f: (13c7) size: 167 off: 37 num: 4 info: 0 rep: 0 fffff1d6: (146e) size: 167 off: 52 num: 4 info: 0 rep: 0 fffff27d: (1515) size: 22 off: 67 num: 4 info: 0 rep: 0 fffff293: (152b) size: 141 off: 82 num: 4 info: 0 rep: 0 fffff320: (15b8) size: 81 off: 97 num: 4 info: 0 rep: 0 fffff371: (1609) size: 671 off: 112 num: 4 info: 1 rep: 0 fffff610: (18a8) size: 171 off: 131 num: 4 info: 0 rep: 0 The above turns was created by a loop of: fde = (void *)sframes + sizeof(*sframes) + sframes->sfh_fdeoff; for (s = 0; s < sframes->sfh_num_fdes; s++, fde++) { printf("\t%x: (%lx) size:%8u off:%8u num:%8u info:%2u rep:%2u\n", fde->sfde_func_start_address, fde->sfde_func_start_address + shdr->sh_offset, fde->sfde_func_size, fde->sfde_func_start_fre_off, fde->sfde_func_num_fres, fde->sfde_func_info, fde->sfde_func_rep_size); } As you can see, all the ip_off are negative. > > ip_off = ip - sec->sframe_addr; > > first = (void __user *)sec->fdes_addr; > - last = first + sec->fdes_nr; > + last = first + sec->fdes_nr - 1; The above was mentioned before. > while (first <= last) { > struct sframe_fde __user *mid; > - u32 func_off; > + s32 func_off; > > mid = first + ((last - first) / 2); > > diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c > index 11aadfade005..d9cd820150c5 100644 > --- a/kernel/unwind/user.c > +++ b/kernel/unwind/user.c > @@ -97,7 +97,7 @@ int unwind_user_start(struct unwind_user_state *state) > > if (current_has_sframe()) > state->type = UNWIND_USER_TYPE_SFRAME; > - else if (IS_ENABLED(CONFIG_UNWIND_USER_FP)) > + else if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP)) This was mentioned too. > state->type = UNWIND_USER_TYPE_FP; > else > state->type = UNWIND_USER_TYPE_NONE; > @@ -138,7 +138,7 @@ int unwind_user(struct unwind_stacktrace *trace, unsigned int max_entries) > static u64 ctx_to_cookie(u64 cpu, u64 ctx) > { > BUILD_BUG_ON(NR_CPUS > 65535); > - return (ctx & ((1UL << 48) - 1)) | cpu; > + return (ctx & ((1UL << 48) - 1)) | (cpu << 48); And so was this. -- Steve > } > > /*