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Howlett" , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , Heiko Carstens , Vasily Gorbik Subject: [PATCH v13 08/18] unwind_user/sframe: Add support for outermost frame indication Date: Tue, 27 Jan 2026 16:05:43 +0100 Message-ID: <20260127150554.2760964-9-jremus@linux.ibm.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com> References: <20260127150554.2760964-1-jremus@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=Z4vh3XRA c=1 sm=1 tr=0 ts=6978d45d cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=vUbySO9Y5rIA: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=mFg4y33aAicYmUfzDuoA:9 a=jhqOcbufqs7Y1TYCrUUU:22 a=1CNFftbPRP8L7MoqJWF3:22 a=HkZW87K1Qel5hWWM3VKY:22 a=wa9RWnbW_A1YIeRBVszw:22 X-Proofpoint-GUID: KlXhgSsl-7XYGr8sEfIy1wcmIpHJAtvp X-Proofpoint-ORIG-GUID: 1nm0Z9teSyeP7GTrC8S6VI-9JvDkzbHB X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTI3MDEyMSBTYWx0ZWRfX8ehchMl53yaJ fhvCTCx2yZ+p/TGN5+RQxrq9+j9wt8NoOUFDFh4LaSJ8mHgL4MfxPbe1jiMBkO2WgFVHakS/7r4 M/vG8tmc6/ZZtysxHnzyfD2QBCzYPHmtaDf8z6PoOSaGsRPGux9TIHoDib4brteX4Kl7RxoOko3 R/BboGphlfMIzq4TYydGBoXM6RQzK9f4qNX3l9SXTf11tarMJYJMd1F3Gzz8JjuoHTmxKCsAKSj Bhqx3M2ObqttbbAkyce1w/34RocYLgP/kLgpIm0eWsYQGgQJppOZ7G3QXRJtMQsmKPeOGpPLt09 5p1uRo/I2tKfrbhz4qa+cwhw2kOhG3IkbrcIJxw3zl7zZ8E9bo90ijYt9EA1yBlHYYHRmBkfO/R MpszybXEApyTC3gxchB+ndVRNUZs8XNDhDXZA57uFhC0OD/V/IT7GHTkPTs0mIAvqbZDzp7ItNT b/PaEexVcRASurcbwHg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-01-27_03,2026-01-27_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 malwarescore=0 phishscore=0 priorityscore=1501 bulkscore=0 adultscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2601270121 X-Rspamd-Queue-Id: E8257100007 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: w4hunzkaqgmgacihhxec7nene8em79md X-HE-Tag: 1769527298-214939 X-HE-Meta: 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 9pHKaKIB 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: SFrame may represent an undefined return address (RA) as SFrame FRE without any offsets as indication for an outermost frame. Cc: Steven Rostedt Cc: Josh Poimboeuf 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: Jens Remus --- Notes (jremus): Changes in v13: - Use SFRAME_V3_FRE_RA_UNDEFINED_P() instead of struct sframe_fre_internal.ra_undefined field. - Reduce indentation of assignments. kernel/unwind/sframe.c | 15 ++++++++++++++- kernel/unwind/sframe.h | 1 + 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index 9b3779924395..6004b43aac34 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -218,7 +218,7 @@ static __always_inline int __read_fre(struct sframe_section *sec, UNSAFE_GET_USER_INC(info, cur, 1, Efault); dataword_count = SFRAME_V3_FRE_DATAWORD_COUNT(info); dataword_size = dataword_size_enum_to_size(SFRAME_V3_FRE_DATAWORD_SIZE(info)); - if (!dataword_count || !dataword_size) + if (!dataword_size) return -EFAULT; if (cur + (dataword_count * dataword_size) > sec->fres_end) @@ -228,6 +228,17 @@ static __always_inline int __read_fre(struct sframe_section *sec, if (fde_type != SFRAME_FDE_TYPE_REGULAR) return -EFAULT; + if (!dataword_count) { + /* + * A FRE without data words indicates RA undefined / + * outermost frame. + */ + cfa_off = 0; + ra_off = 0; + fp_off = 0; + goto done; + } + UNSAFE_GET_USER_INC(cfa_off, cur, dataword_size, Efault); dataword_count--; @@ -248,6 +259,7 @@ static __always_inline int __read_fre(struct sframe_section *sec, if (dataword_count) return -EFAULT; +done: fre->size = addr_size + 1 + (dataword_count * dataword_size); fre->ip_off = ip_off; fre->cfa_off = cfa_off; @@ -314,6 +326,7 @@ static __always_inline int __find_fre(struct sframe_section *sec, frame->ra_off = fre->ra_off; frame->fp_off = fre->fp_off; frame->use_fp = SFRAME_V3_FRE_CFA_BASE_REG_ID(fre->info) == SFRAME_BASE_REG_FP; + frame->outermost = SFRAME_V3_FRE_RA_UNDEFINED_P(fre->info); return 0; } diff --git a/kernel/unwind/sframe.h b/kernel/unwind/sframe.h index 07a2e99855f9..3fcc15534e5a 100644 --- a/kernel/unwind/sframe.h +++ b/kernel/unwind/sframe.h @@ -77,5 +77,6 @@ struct sframe_fda_v3 { #define SFRAME_V3_FRE_DATAWORD_COUNT(info) (((info) >> 1) & 0xf) #define SFRAME_V3_FRE_DATAWORD_SIZE(info) (((info) >> 5) & 0x3) #define SFRAME_V3_AARCH64_FRE_MANGLED_RA_P(info) (((info) >> 7) & 0x1) +#define SFRAME_V3_FRE_RA_UNDEFINED_P(info) (SFRAME_V3_FRE_DATAWORD_COUNT(info) == 0) #endif /* _SFRAME_H */ -- 2.51.0