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Marchesi" , Beau Belgrave , Linus Torvalds , Andrew Morton , Florian Weimer , Kees Cook , "Carlos O'Donell" , Sam James , Dylan Hatch , Borislav Petkov , Dave Hansen , David Hildenbrand , "H. Peter Anvin" , "Liam R. Howlett" , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , Heiko Carstens , Vasily Gorbik , "Steven Rostedt (Google)" Subject: [PATCH v12 12/13] unwind_user/sframe: Add .sframe validation option Date: Wed, 19 Nov 2025 14:23:22 +0100 Message-ID: <20251119132323.1281768-13-jremus@linux.ibm.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20251119132323.1281768-1-jremus@linux.ibm.com> References: <20251119132323.1281768-1-jremus@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-GUID: -ktxfelSEHO1S0-x_8XUubXNlHmX4VLn X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTE1MDAzMiBTYWx0ZWRfXxdKepSesuO9q yrignO2mA/haT12FscE2kh9D8BmR0a+5iFNzC2cLfmXbCIgr8YMIcGMJ58pWMSzJGm7e1kqBZ8J F7H4jSXce859bkoUa7Cs4EKfSws3BAfJB5Vcczt7apv5sSdXF0DD9IOI2ArdOLYUWk/G0eQTcgh rvb7lQtn+ZNxiZg7qiOidjHT36dxQi4/wcZ5rGYmN2NXeTvrI8h1ti4dXqk0Bq+3qRKU/PSqZMU krRb30d+UObAd4uahOyJu/MSKigoK5G/eIgSX7peNuFjyJJdz27zoblVdEhMqC1c2o+torAx01z pKWtAjCUzge6gML6kVDgBS7h00otSmvBN1b4m/iSiIJE5RwI3MfTEoS+DlE4EVoXJLyw/k92I3N oPWNU1oQLwI7jLog2qb3+NGmgjxRVA== X-Proofpoint-ORIG-GUID: e1BxXyBm0ZA4EiM_3N3mCpNoscNDoDVH X-Authority-Analysis: v=2.4 cv=XtL3+FF9 c=1 sm=1 tr=0 ts=691dc4da cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=7d_E57ReAAAA:8 a=JfrnYn6hAAAA:8 a=yPCof4ZbAAAA:8 a=mDV3o1hIAAAA:8 a=yMhMjlubAAAA:8 a=VnNF1IyMAAAA:8 a=Z4Rwk6OoAAAA:8 a=20KFwNOVAAAA:8 a=7mOBRU54AAAA:8 a=meVymXHHAAAA:8 a=RXKZOtKmAAAA:8 a=X__uKv6Ezr3YNgStCWAA:9 a=jhqOcbufqs7Y1TYCrUUU:22 a=1CNFftbPRP8L7MoqJWF3:22 a=HkZW87K1Qel5hWWM3VKY:22 a=wa9RWnbW_A1YIeRBVszw:22 a=2JgSa4NbpEOStq-L5dxp:22 a=UFF3uGjEBZWolfm0k6KQ:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-19_04,2025-11-18_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 spamscore=0 bulkscore=0 priorityscore=1501 impostorscore=0 adultscore=0 lowpriorityscore=0 phishscore=0 suspectscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511150032 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. [ Jens Remus: Add support for PC-relative FDE function start address. Adjust to rename of struct sframe_fre to sframe_fre_internal. ] Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Jiri Olsa Cc: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Thomas Gleixner Cc: Andrii Nakryiko Cc: Indu Bhagat Cc: "Jose E. Marchesi" Cc: Beau Belgrave Cc: Jens Remus Cc: Linus Torvalds Cc: Andrew Morton Cc: Florian Weimer Cc: Sam James Cc: Kees Cook Cc: "Carlos O'Donell" Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) Signed-off-by: Jens Remus --- Notes (jremus): Changes in v12: - Adjust to use internal SFrame FDE representation. - Adjust to rename of struct sframe_fre to sframe_fre_internal. =20 Changes in v11: - Support for SFrame V2 PC-relative FDE function start address. arch/Kconfig | 19 +++++++++ kernel/unwind/sframe.c | 97 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 116 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index ab1941ef1411..06c4f909398c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -493,6 +493,25 @@ config HAVE_UNWIND_USER_SFRAME bool select UNWIND_USER =20 +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 7d3e286c1b23..6465e7a315bc 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -351,6 +351,99 @@ int sframe_find(unsigned long ip, struct unwind_user_f= rame *frame) return ret; } =20 +#ifdef CONFIG_SFRAME_VALIDATION + +static int safe_read_fde(struct sframe_section *sec, + unsigned int fde_num, struct sframe_fde_internal *fde) +{ + int ret; + + if (!user_read_access_begin((void __user *)sec->sframe_start, + sec->sframe_end - sec->sframe_start)) + return -EFAULT; + ret =3D __read_fde(sec, fde_num, fde); + user_read_access_end(); + return ret; +} + +static int safe_read_fre(struct sframe_section *sec, + struct sframe_fde_internal *fde, + unsigned long fre_addr, + struct sframe_fre_internal *fre) +{ + int ret; + + if (!user_read_access_begin((void __user *)sec->sframe_start, + sec->sframe_end - sec->sframe_start)) + return -EFAULT; + ret =3D __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 =3D 0; + unsigned int i; + + for (i =3D 0; i < sec->num_fdes; i++) { + struct sframe_fre_internal *fre, *prev_fre =3D NULL; + unsigned long ip, fre_addr; + struct sframe_fde_internal fde; + struct sframe_fre_internal fres[2]; + bool which =3D false; + unsigned int j; + int ret; + + ret =3D safe_read_fde(sec, i, &fde); + if (ret) + return ret; + + ip =3D fde.func_start_addr; + if (ip <=3D prev_ip) { + dbg_sec("fde %u not sorted\n", i); + return -EFAULT; + } + prev_ip =3D ip; + + fre_addr =3D sec->fres_start + fde.fres_off; + for (j =3D 0; j < fde.fres_num; j++) { + int ret; + + fre =3D which ? fres : fres + 1; + which =3D !which; + + ret =3D safe_read_fre(sec, &fde, fre_addr, fre); + if (ret) { + dbg_sec("fde %u: __read_fre(%u) failed\n", i, j); + dbg_sec("FDE: func_start_addr:0x%lx func_size:0x%x fres_off:0x%x fres_= num:%d info:%u rep_size:%u\n", + fde.func_start_addr, fde.func_size, + fde.fres_off, fde.fres_num, + fde.info, fde.rep_size); + return ret; + } + + fre_addr +=3D fre->size; + + if (prev_fre && fre->ip_off <=3D prev_fre->ip_off) { + dbg_sec("fde %u: fre %u not sorted\n", i, j); + return -EFAULT; + } + + prev_fre =3D 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); @@ -460,6 +553,10 @@ int sframe_add_section(unsigned long sframe_start, uns= igned long sframe_end, goto err_free; } =20 + ret =3D sframe_validate_section(sec); + if (ret) + goto err_free; + ret =3D mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec= , GFP_KERNEL); if (ret) { dbg_sec("mtree_insert_range failed: text=3D%lx-%lx\n", --=20 2.48.1