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Peter Anvin" , Mathieu Desnoyers , Kees Cook , Sam James Cc: Jens Remus , bpf@vger.kernel.org, linux-mm@kvack.org, Namhyung Kim , Andrii Nakryiko , "Jose E. Marchesi" , Beau Belgrave , Florian Weimer , "Carlos O'Donell" , Masami Hiramatsu , Jiri Olsa , Arnaldo Carvalho de Melo , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Heiko Carstens , Vasily Gorbik , Ilya Leoshkevich , "Steven Rostedt (Google)" Subject: [PATCH v16 03/20] unwind_user/sframe: Store .sframe section data in per-mm maple tree Date: Thu, 21 May 2026 16:25:29 +0200 Message-ID: <20260521142546.3908498-4-jremus@linux.ibm.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260521142546.3908498-1-jremus@linux.ibm.com> References: <20260521142546.3908498-1-jremus@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTIxMDE0MiBTYWx0ZWRfXy2kGxoTWZUbO a78ioVhmxv/1Lm6FHJOueC62PP3+MWmHHI1LNaxZaU1/sMIILjZAjT69q9xw97AE2rPM35YbPd4 gaK+i8KjVGnA/DPvNwGk+9FdMTSBXevGhIUvhYRsQNS8wgCotPd/44FysqH0kuiC4C+Vjg0ulxI zIElyF56mFunOuO/U27DsVUEZosxGszceqVawJx0IMF1dQIxz1dvcR+0Hn5LLGSP/41LYjj/0xg S1bV8ARPvlSJnTdhhtsn4CyuXl0msuJ4YqYJGE4jrc7yqpEC4hw5PrNSAho48BkePXOePCl1hA8 3LRvXLOCoFH5xXpe3oeZD1vekiI5wZXmjnF8D8YL20ufSL/KuqGLZeu4Sh8oWenjIzAYGDeYcD2 +nDEf4Mc+cglk6Rwg2HG8p0AlTbysoCwVlDnn9ssvY+FylxYzH7blxHVIDkZtGmCZIEcNCyr+XL ZVrW1XNiY0DrdGoMgJA== X-Authority-Analysis: v=2.4 cv=BNuDalQG c=1 sm=1 tr=0 ts=6a0f15f3 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VwQbUJbxAAAA:8 a=meVymXHHAAAA:8 a=pGLkceISAAAA:8 a=VnNF1IyMAAAA:8 a=kG-nbKyDqmrV4dykLI8A:9 a=2JgSa4NbpEOStq-L5dxp:22 X-Proofpoint-ORIG-GUID: Yj0LaF0FkTic88FYSwchjc-y2t1JuMc4 X-Proofpoint-GUID: quXsH3SVjBwEiRlwOCP6xl2xWRlzy7vU X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-21_02,2026-05-18_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 malwarescore=0 impostorscore=0 suspectscore=0 lowpriorityscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605130000 definitions=main-2605210142 From: Josh Poimboeuf Associate an .sframe section with its mm by adding it to a per-mm maple tree which is indexed by the corresponding text address range. A single .sframe section can be associated with multiple text ranges. [ Jens Remus: Minor cleanups. Reword commit subject/message. ] Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) Reviewed-by: Indu Bhagat Signed-off-by: Jens Remus --- Notes (jremus): Changes in v16: - Move SRCU definitions from patch "unwind_user/sframe: Add support for reading .sframe contents" here. (Sashiko AI) Changes in v15: - Fix text section end passed to mtree_insert_range() to be inclusive. (Sashiko AI) - sframe_remove_section(): Add guard(srcu) to guard access to sec->sframe_start. This also guards access to sec->filename in __sframe_remove_section(). (Sashiko AI) - Use GFP_KERNEL_ACCOUNT instead of GFP_KERNEL (see memory-allocation.rst, section "Get Free Page flags"). (Sashiko AI) arch/x86/include/asm/mmu.h | 2 +- include/linux/mm_types.h | 3 ++ include/linux/sframe.h | 18 ++++++++++ kernel/fork.c | 10 ++++++ kernel/unwind/sframe.c | 68 ++++++++++++++++++++++++++++++++++++-- mm/init-mm.c | 2 ++ 6 files changed, 99 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 0fe9c569d171..227a32899a59 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -87,7 +87,7 @@ typedef struct { .context = { \ .ctx_id = 1, \ .lock = __MUTEX_INITIALIZER(mm.context.lock), \ - } + }, void leave_mm(void); #define leave_mm leave_mm diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index a308e2c23b82..c1505356b6fc 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1424,6 +1424,9 @@ struct mm_struct { #ifdef CONFIG_MM_ID mm_id_t mm_id; #endif /* CONFIG_MM_ID */ +#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME + struct maple_tree sframe_mt; +#endif } __randomize_layout; /* diff --git a/include/linux/sframe.h b/include/linux/sframe.h index 0642595534f9..38047760e252 100644 --- a/include/linux/sframe.h +++ b/include/linux/sframe.h @@ -2,9 +2,14 @@ #ifndef _LINUX_SFRAME_H #define _LINUX_SFRAME_H +#include +#include + #ifdef CONFIG_HAVE_UNWIND_USER_SFRAME struct sframe_section { + struct rcu_head rcu; + unsigned long sframe_start; unsigned long sframe_end; unsigned long text_start; @@ -19,18 +24,31 @@ struct sframe_section { signed char fp_off; }; +#define INIT_MM_SFRAME .sframe_mt = MTREE_INIT(sframe_mt, 0), +extern void sframe_free_mm(struct mm_struct *mm); + extern int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, unsigned long text_start, unsigned long text_end); extern int sframe_remove_section(unsigned long sframe_addr); +static inline bool current_has_sframe(void) +{ + struct mm_struct *mm = current->mm; + + return mm && !mtree_empty(&mm->sframe_mt); +} + #else /* !CONFIG_HAVE_UNWIND_USER_SFRAME */ +#define INIT_MM_SFRAME +static inline void sframe_free_mm(struct mm_struct *mm) {} static inline int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, unsigned long text_start, unsigned long text_end) { return -ENOSYS; } static inline int sframe_remove_section(unsigned long sframe_addr) { return -ENOSYS; } +static inline bool current_has_sframe(void) { return false; } #endif /* CONFIG_HAVE_UNWIND_USER_SFRAME */ diff --git a/kernel/fork.c b/kernel/fork.c index 5f3fdfdb14c7..8d8195561c95 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -110,6 +110,7 @@ #include #include #include +#include #include #include @@ -735,6 +736,7 @@ void __mmdrop(struct mm_struct *mm) mm_pasid_drop(mm); mm_destroy_cid(mm); percpu_counter_destroy_many(mm->rss_stat, NR_MM_COUNTERS); + sframe_free_mm(mm); free_mm(mm); } @@ -1072,6 +1074,13 @@ static void mmap_init_lock(struct mm_struct *mm) #endif } +static void mm_init_sframe(struct mm_struct *mm) +{ +#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME + mt_init(&mm->sframe_mt); +#endif +} + static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, struct user_namespace *user_ns) { @@ -1100,6 +1109,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm->pmd_huge_pte = NULL; #endif mm_init_uprobes_state(mm); + mm_init_sframe(mm); hugetlb_count_init(mm); mm_flags_clear_all(mm); diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index d24e9d4f8bef..46dba3cb016d 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -19,6 +19,8 @@ #define dbg(fmt, ...) \ pr_debug("%s (%d): " fmt, current->comm, current->pid, ##__VA_ARGS__) +DEFINE_STATIC_SRCU(sframe_srcu); + static void free_section(struct sframe_section *sec) { kfree(sec); @@ -81,6 +83,7 @@ static int sframe_read_header(struct sframe_section *sec) int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, unsigned long text_start, unsigned long text_end) { + struct maple_tree *sframe_mt = ¤t->mm->sframe_mt; struct vm_area_struct *sframe_vma, *text_vma; struct mm_struct *mm = current->mm; struct sframe_section *sec; @@ -122,15 +125,74 @@ int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, if (ret) goto err_free; - /* TODO nowhere to store it yet - just free it and return an error */ - ret = -ENOSYS; + ret = mtree_insert_range(sframe_mt, sec->text_start, sec->text_end - 1, + sec, GFP_KERNEL_ACCOUNT); + if (ret) { + dbg("mtree_insert_range failed: text=%lx-%lx\n", + sec->text_start, sec->text_end); + goto err_free; + } + + return 0; err_free: free_section(sec); return ret; } +static void sframe_free_srcu(struct rcu_head *rcu) +{ + struct sframe_section *sec = container_of(rcu, struct sframe_section, rcu); + + free_section(sec); +} + +static int __sframe_remove_section(struct mm_struct *mm, + struct sframe_section *sec) +{ + if (!mtree_erase(&mm->sframe_mt, sec->text_start)) { + dbg("mtree_erase failed: text=%lx\n", sec->text_start); + return -EINVAL; + } + + call_srcu(&sframe_srcu, &sec->rcu, sframe_free_srcu); + + return 0; +} + int sframe_remove_section(unsigned long sframe_start) { - return -ENOSYS; + struct mm_struct *mm = current->mm; + struct sframe_section *sec; + unsigned long index = 0; + bool found = false; + int ret = 0; + + guard(srcu)(&sframe_srcu); + + mt_for_each(&mm->sframe_mt, sec, index, ULONG_MAX) { + if (sec->sframe_start == sframe_start) { + found = true; + ret |= __sframe_remove_section(mm, sec); + } + } + + if (!found || ret) + return -EINVAL; + + return 0; +} + +void sframe_free_mm(struct mm_struct *mm) +{ + struct sframe_section *sec; + unsigned long index = 0; + + if (!mm) + return; + + mt_for_each(&mm->sframe_mt, sec, index, ULONG_MAX) + free_section(sec); + + mtree_destroy(&mm->sframe_mt); } diff --git a/mm/init-mm.c b/mm/init-mm.c index c5556bb9d5f0..77909139162e 100644 --- a/mm/init-mm.c +++ b/mm/init-mm.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #ifndef INIT_MM_CONTEXT @@ -49,6 +50,7 @@ struct mm_struct init_mm = { #endif .flexible_array = MM_STRUCT_FLEXIBLE_ARRAY_INIT, INIT_MM_CONTEXT(init_mm) + INIT_MM_SFRAME }; void setup_initial_init_mm(void *start_code, void *end_code, -- 2.51.0