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Wed, 6 Nov 2024 17:04:08 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 611BA20040; Wed, 6 Nov 2024 17:04:08 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 17B1320043; Wed, 6 Nov 2024 17:04:07 +0000 (GMT) Received: from [9.152.222.93] (unknown [9.152.222.93]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 6 Nov 2024 17:04:07 +0000 (GMT) Message-ID: Date: Wed, 6 Nov 2024 18:04:06 +0100 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 09/19] unwind: Introduce sframe user space unwinding To: Josh Poimboeuf , x86@kernel.org Cc: Peter Zijlstra , Steven Rostedt , 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.kerne.org, Andrii Nakryiko , Mathieu Desnoyers , Florian Weimer , Andy Lutomirski , Heiko Carstens , Vasily Gorbik References: <42c0a99236af65c09c8182e260af7bcf5aa1e158.1730150953.git.jpoimboe@kernel.org> From: Jens Remus Content-Language: en-US Organization: IBM Deutschland Research & Development GmbH In-Reply-To: <42c0a99236af65c09c8182e260af7bcf5aa1e158.1730150953.git.jpoimboe@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed X-TM-AS-GCONF: 00 X-Proofpoint-GUID: ZWjQAsrbLnnnQrWJyHlh0lryrAE7UvIA X-Proofpoint-ORIG-GUID: M9vnOA56mAYv8FrsMXCtZQaJeayKSw9c Content-Transfer-Encoding: 8bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten Precedence: bulk X-Mailing-List: linux-toolchains@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 suspectscore=0 clxscore=1015 adultscore=0 malwarescore=0 priorityscore=1501 phishscore=0 impostorscore=0 lowpriorityscore=0 mlxscore=0 mlxlogscore=999 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2409260000 definitions=main-2411060133 On 28.10.2024 22:47, Josh Poimboeuf wrote: ... > diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c ... > +#define __SFRAME_GET_USER(out, user_ptr, type) \ > +({ \ > + type __tmp; \ > + if (get_user(__tmp, (type __user *)user_ptr)) \ > + return -EFAULT; \ > + user_ptr += sizeof(__tmp); \ > + out = __tmp; \ > +}) > + > +#define SFRAME_GET_USER(out, user_ptr, size) \ > +({ \ > + switch (size) { \ > + case 1: \ > + __SFRAME_GET_USER(out, user_ptr, u8); \ > + break; \ > + case 2: \ > + __SFRAME_GET_USER(out, user_ptr, u16); \ > + break; \ > + case 4: \ > + __SFRAME_GET_USER(out, user_ptr, u32); \ > + break; \ > + default: \ > + return -EINVAL; \ > + } \ > +}) > + > +static unsigned char fre_type_to_size(unsigned char fre_type) > +{ > + if (fre_type > 2) > + return 0; > + return 1 << fre_type; > +} > + > +static unsigned char offset_size_enum_to_size(unsigned char off_size) > +{ > + if (off_size > 2) > + return 0; > + return 1 << off_size; > +} ... > +static int find_fre(struct sframe_section *sec, struct sframe_fde *fde, > + unsigned long ip, struct unwind_user_frame *frame) > +{ > + unsigned char fde_type = SFRAME_FUNC_FDE_TYPE(fde->info); > + unsigned char fre_type = SFRAME_FUNC_FRE_TYPE(fde->info); > + unsigned char offset_count, offset_size; > + s32 cfa_off, ra_off, fp_off, ip_off; > + void __user *f, *last_f = NULL; > + unsigned char addr_size; > + u32 last_fre_ip_off = 0; > + u8 fre_info = 0; > + int i; > + > + addr_size = fre_type_to_size(fre_type); > + if (!addr_size) > + return -EINVAL; > + > + ip_off = ip - (sec->sframe_addr + fde->start_addr); > + > + f = (void __user *)sec->fres_addr + fde->fres_off; > + > + for (i = 0; i < fde->fres_num; i++) { > + u32 fre_ip_off; > + > + SFRAME_GET_USER(fre_ip_off, f, addr_size); > + > + if (fre_ip_off < last_fre_ip_off) > + return -EINVAL; > + > + last_fre_ip_off = fre_ip_off; > + > + if (fde_type == SFRAME_FDE_TYPE_PCINC) { > + if (ip_off < fre_ip_off) > + break; > + } else { > + /* SFRAME_FDE_TYPE_PCMASK */ > + if (ip_off % fde->rep_size < fre_ip_off) > + break; > + } > + > + SFRAME_GET_USER(fre_info, f, 1); > + > + offset_count = SFRAME_FRE_OFFSET_COUNT(fre_info); > + offset_size = offset_size_enum_to_size(SFRAME_FRE_OFFSET_SIZE(fre_info)); > + > + if (!offset_count || !offset_size) > + return -EINVAL; > + > + last_f = f; > + f += offset_count * offset_size; > + } > + > + if (!last_f) > + return -EINVAL; > + > + f = last_f; > + > + SFRAME_GET_USER(cfa_off, f, offset_size); SFRAME_GET_USER() does not work for the signed SFrame CFA offset. > + offset_count--; > + > + ra_off = sec->ra_off; > + if (!ra_off) { > + if (!offset_count--) > + return -EINVAL; > + > + SFRAME_GET_USER(ra_off, f, offset_size); Likewise for the signed SFrame RA offset. Excerpt from my added trace. Note the RA_off=65488 (unsigned) = 0xFFD0 = -48 (signed): unwind_user_next: WARNING: RA could not be obtained from user space (IP=0x000003ffbb5f4218, CFA=0x000003ffc22f8f10, RA_off=65488) Excerpt from perf script: 3ffbb5f4218 internal_fnwmatch+0x558 (/usr/lib64/libc.so.6) Excerpts from objdump -wt --sframe: 00000000000f3cc0 l F .text 000000000000195c internal_fnwmatch func idx [1715]: pc = 0xf3cc0, size = 6492 bytes STARTPC CFA FP RA INFO 00000000000f3cc0 sp+160 u u (1*1B) 00000000000f3cc6 sp+160 c-72 c-48 (3*1B) 00000000000f3cd0 sp+4256 c-72 c-48 (3*2B) 00000000000f3cdc sp+8352 c-72 c-48 (3*2B) 00000000000f3ce8 sp+10792 c-72 c-48 (3*2B) 00000000000f3f7e sp+160 u u (1*1B) 00000000000f3f80 sp+10792 c-72 c-48 (3*2B) > + } > + > + fp_off = sec->fp_off; > + if (!fp_off && offset_count) { > + offset_count--; > + SFRAME_GET_USER(fp_off, f, offset_size); Likewise for the signed SFrame FP offset. > + } > + > + if (offset_count) > + return -EINVAL; > + > + frame->cfa_off = cfa_off; > + frame->ra_off = ra_off; > + frame->fp_off = fp_off; > + frame->use_fp = SFRAME_FRE_CFA_BASE_REG_ID(fre_info) == SFRAME_BASE_REG_FP; > + > + return 0; > +} ... I have verified that reintroducing and using SFRAME_GET_USER_SIGNED() works correctly. Regards, Jens -- Jens Remus Linux on Z Development (D3303) and z/VSE Support +49-7031-16-1128 Office jremus@de.ibm.com IBM IBM Deutschland Research & Development GmbH; Vorsitzender des Aufsichtsrats: Wolfgang Wendt; Geschäftsführung: David Faller; Sitz der Gesellschaft: Böblingen; Registergericht: Amtsgericht Stuttgart, HRB 243294 IBM Data Privacy Statement: https://www.ibm.com/privacy/