From: Steven Rostedt <[email protected]>
Add system calls to register and unregister sframes that can be used by
dynamic linkers to tell the kernel where the sframe section is in memory
for libraries it loads.
Both system calls take a pointer to a new structure:
struct sframe_setup {
unsigned long sframe_start;
unsigned long sframe_size;
unsigned long text_start;
unsigned long text_size;
};
and a size of the passed in structure. If the system call needs to be
extended, then the structure could be changed and the size of that
structure will tell the kernel that it is the new version. If the kernel
does not recognize the structure size, it will return -EINVAL.
sframe_start - The virtual address of the sframe section
sframe_size - The length of the sframe section
text_start - the text section the sframe represents
test_size - the length of the section
If other stack tracing functionality is added, it will require a new
system call.
The unregister only needs the sframe_start and requires all the rest of
the fields to be 0. In the future, if more can be done, then user space
can update the other values and check the return code to see if the kernel
supports it.
Signed-off-by: Steven Rostedt <[email protected]>
---
Based on top of Jens patches here:
https://lore.kernel.org/linux-trace-kernel/[email protected]/
[ Note, I tested this with the same program from the RFC patch ]
Changes from RFC:
https://patch.msgid.link/[email protected]
- Remove the ioctl() like system call for a unique system call for each
functionality. Right now there's two functionalities:
1. register sframe section
2. unregister sframe sections
- Added taking a lock around the mtree logic in __sframe_remove_section()
as Sashiko mentioned that there could be races from user space
registering and unregistering sframe sections at the same time.
- Removed [RFC] from subject as I believe this is more likely the way
this system call will be done.
arch/alpha/kernel/syscalls/syscall.tbl | 2 +
arch/arm/tools/syscall.tbl | 2 +
arch/arm64/tools/syscall_32.tbl | 2 +
arch/m68k/kernel/syscalls/syscall.tbl | 2 +
arch/microblaze/kernel/syscalls/syscall.tbl | 2 +
arch/mips/kernel/syscalls/syscall_n32.tbl | 2 +
arch/mips/kernel/syscalls/syscall_n64.tbl | 2 +
arch/mips/kernel/syscalls/syscall_o32.tbl | 2 +
arch/parisc/kernel/syscalls/syscall.tbl | 2 +
arch/powerpc/kernel/syscalls/syscall.tbl | 2 +
arch/s390/kernel/syscalls/syscall.tbl | 3 +
arch/sh/kernel/syscalls/syscall.tbl | 2 +
arch/sparc/kernel/syscalls/syscall.tbl | 2 +
arch/x86/entry/syscalls/syscall_32.tbl | 2 +
arch/x86/entry/syscalls/syscall_64.tbl | 2 +
arch/xtensa/kernel/syscalls/syscall.tbl | 2 +
include/linux/syscalls.h | 2 +
include/uapi/asm-generic/unistd.h | 7 ++-
include/uapi/linux/sframe.h | 12 ++++
kernel/sys_ni.c | 3 +
kernel/unwind/sframe.c | 63 ++++++++++++++++++++-
scripts/syscall.tbl | 2 +
22 files changed, 118 insertions(+), 4 deletions(-)
create mode 100644 include/uapi/linux/sframe.h
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl
b/arch/alpha/kernel/syscalls/syscall.tbl
index f31b7afffc34..f0639b831f2a 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -511,3 +511,5 @@
579 common file_setattr sys_file_setattr
580 common listns sys_listns
581 common rseq_slice_yield sys_rseq_slice_yield
+582 common sframe_register sys_sframe_register
+583 common sframe_unregister sys_sframe_unregister
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 94351e22bfcf..887b242ffb25 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -486,3 +486,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/arch/arm64/tools/syscall_32.tbl b/arch/arm64/tools/syscall_32.tbl
index 62d93d88e0fe..c820f1ff718c 100644
--- a/arch/arm64/tools/syscall_32.tbl
+++ b/arch/arm64/tools/syscall_32.tbl
@@ -483,3 +483,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl
b/arch/m68k/kernel/syscalls/syscall.tbl
index 248934257101..4c7f17f0364b 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -471,3 +471,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl
b/arch/microblaze/kernel/syscalls/syscall.tbl
index 223d26303627..e8dc2cc149f4 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -477,3 +477,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl
b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 7430714e2b8f..d0bae05d16af 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -410,3 +410,5 @@
469 n32 file_setattr sys_file_setattr
470 n32 listns sys_listns
471 n32 rseq_slice_yield sys_rseq_slice_yield
+472 n32 sframe_register sys_sframe_register
+473 n32 sframe_unregister sys_sframe_unregister
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl
b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 630aab9e5425..2e200de6a58c 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -386,3 +386,5 @@
469 n64 file_setattr sys_file_setattr
470 n64 listns sys_listns
471 n64 rseq_slice_yield sys_rseq_slice_yield
+472 n64 sframe_register sys_sframe_register
+473 n64 sframe_unregister sys_sframe_unregister
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl
b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 128653112284..0e3b82011ae2 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -459,3 +459,5 @@
469 o32 file_setattr sys_file_setattr
470 o32 listns sys_listns
471 o32 rseq_slice_yield sys_rseq_slice_yield
+472 o32 sframe_register sys_sframe_register
+473 o32 sframe_unregister sys_sframe_unregister
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl
b/arch/parisc/kernel/syscalls/syscall.tbl
index c6331dad9461..e0758ef8667d 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -470,3 +470,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl
b/arch/powerpc/kernel/syscalls/syscall.tbl
index 4fcc7c58a105..eda40c4f4f2f 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -562,3 +562,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 nospu rseq_slice_yield sys_rseq_slice_yield
+472 nospu sframe_register sys_sframe_register
+473 nospu sframe_unregister sys_sframe_unregister
diff --git a/arch/s390/kernel/syscalls/syscall.tbl
b/arch/s390/kernel/syscalls/syscall.tbl
index 09a7ef04d979..52519e2acdc8 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -398,3 +398,6 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common stacktrace_setup sys_stacktrace_setup
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/arch/sh/kernel/syscalls/syscall.tbl
b/arch/sh/kernel/syscalls/syscall.tbl
index 70b315cbe710..62ac7b1b4dd4 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -475,3 +475,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl
b/arch/sparc/kernel/syscalls/syscall.tbl
index 7e71bf7fcd14..f92273ae608a 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -517,3 +517,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl
b/arch/x86/entry/syscalls/syscall_32.tbl
index f832ebd2d79b..409a50df3b21 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -477,3 +477,5 @@
469 i386 file_setattr sys_file_setattr
470 i386 listns sys_listns
471 i386 rseq_slice_yield sys_rseq_slice_yield
+472 i386 sframe_register sys_sframe_register
+473 i386 sframe_unregister sys_sframe_unregister
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl
b/arch/x86/entry/syscalls/syscall_64.tbl
index 524155d655da..9b7c5a449751 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -396,6 +396,8 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
#
# Due to a historical design error, certain syscalls are numbered differently
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl
b/arch/xtensa/kernel/syscalls/syscall.tbl
index a9bca4e484de..037b8040f69d 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -442,3 +442,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register' sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index f5639d5ac331..992ccc401c5e 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -999,6 +999,8 @@ asmlinkage long sys_lsm_get_self_attr(unsigned int attr,
struct lsm_ctx __user *
asmlinkage long sys_lsm_set_self_attr(unsigned int attr, struct lsm_ctx __user
*ctx,
u32 size, u32 flags);
asmlinkage long sys_lsm_list_modules(u64 __user *ids, u32 __user *size, u32
flags);
+asmlinkage long sys_sframe_register(void *data, unsigned int size);
+asmlinkage long sys_sframe_unregister(void *data, unsigned int size);
/*
* Architecture-specific system calls
diff --git a/include/uapi/asm-generic/unistd.h
b/include/uapi/asm-generic/unistd.h
index a627acc8fb5f..17042d7e5e87 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -863,8 +863,13 @@ __SYSCALL(__NR_listns, sys_listns)
#define __NR_rseq_slice_yield 471
__SYSCALL(__NR_rseq_slice_yield, sys_rseq_slice_yield)
+#define __NR_sframe_register 472
+__SYSCALL(__NR_sframe_register, sys_sframe_register)
+#define __NR_sframe_unregister 473
+__SYSCALL(__NR_sframe_unregister, sys_sframe_unregister)
+
#undef __NR_syscalls
-#define __NR_syscalls 472
+#define __NR_syscalls 474
/*
* 32 bit systems traditionally used different
diff --git a/include/uapi/linux/sframe.h b/include/uapi/linux/sframe.h
new file mode 100644
index 000000000000..137a2ebf91f4
--- /dev/null
+++ b/include/uapi/linux/sframe.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_SFRAME_H
+#define _UAPI_LINUX_SFRAME_H
+
+struct sframe_setup {
+ unsigned long sframe_start;
+ unsigned long sframe_size;
+ unsigned long text_start;
+ unsigned long text_size;
+};
+
+#endif /* _UAPI_LINUX_SFRAME_H */
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index add3032da16f..eca5293f5d40 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -394,3 +394,6 @@ COND_SYSCALL(rseq_slice_yield);
COND_SYSCALL(uretprobe);
COND_SYSCALL(uprobe);
+
+COND_SYSCALL(sframe_register);
+COND_SYSCALL(sframe_unregister);
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index db88d993dff1..9956f1e3aba1 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -12,8 +12,10 @@
#include <linux/mm.h>
#include <linux/string_helpers.h>
#include <linux/sframe.h>
+#include <linux/syscalls.h>
#include <asm/unwind_user_sframe.h>
#include <linux/unwind_user_types.h>
+#include <uapi/linux/sframe.h>
#include "sframe.h"
#include "sframe_debug.h"
@@ -842,9 +844,11 @@ static void sframe_free_srcu(struct rcu_head *rcu)
static int __sframe_remove_section(struct mm_struct *mm,
struct sframe_section *sec)
{
- if (!mtree_erase(&mm->sframe_mt, sec->text_start)) {
- dbg_sec("mtree_erase failed: text=%lx\n", sec->text_start);
- return -EINVAL;
+ scoped_guard(mmap_read_lock, mm) {
+ if (!mtree_erase(&mm->sframe_mt, sec->text_start)) {
+ dbg_sec("mtree_erase failed: text=%lx\n",
sec->text_start);
+ return -EINVAL;
+ }
}
call_srcu(&sframe_srcu, &sec->rcu, sframe_free_srcu);
@@ -936,3 +940,56 @@ void sframe_free_mm(struct mm_struct *mm)
mtree_destroy(&mm->sframe_mt);
}
+
+/**
+ * sys_sframe_register - register an address for user space stacktrace walking.
+ * @data: Structure of sframe data used to register the sframe section
+ * @size: The size of the given structure.
+ *
+ * This system call is used by dynamic library utilities to inform the kernel
+ * of meta data that it loaded that can be used by the kernel to know how
+ * to stack walk the given text locations.
+ *
+ * Return: 0 if successful, otherwise a negative error.
+ */
+SYSCALL_DEFINE2(sframe_register, __user struct sframe_setup *, data, unsigned
int, size)
+{
+ struct sframe_setup sframe;
+
+ if (sizeof(sframe) != size)
+ return -EINVAL;
+
+ if (copy_from_user(&sframe, data, size))
+ return -EFAULT;
+
+ return sframe_add_section(sframe.sframe_start,
+ sframe.sframe_start + sframe.sframe_size,
+ sframe.text_start,
+ sframe.text_start + sframe.text_size);
+}
+
+/**
+ * sys_sframe_unregister - unregister an sframe address
+ * @data: Structure of sframe data used to register the sframe section
+ * @size: The size of the given structure.
+ *
+ * The data->sframe_start is the only value that is used. The rest must
+ * be zero.
+ *
+ * Return: 0 if successful, otherwise a negative error.
+ */
+SYSCALL_DEFINE2(sframe_unregister, __user struct sframe_setup *, data,
unsigned int, size)
+{
+ struct sframe_setup sframe;
+
+ if (sizeof(sframe) != size)
+ return -EINVAL;
+
+ if (copy_from_user(&sframe, data, size))
+ return -EFAULT;
+
+ if (sframe.sframe_size || sframe.text_start || sframe.text_size)
+ return -EINVAL;
+
+ return sframe_remove_section(sframe.sframe_start);
+}
diff --git a/scripts/syscall.tbl b/scripts/syscall.tbl
index 7a42b32b6577..46ec22b50042 100644
--- a/scripts/syscall.tbl
+++ b/scripts/syscall.tbl
@@ -412,3 +412,5 @@
469 common file_setattr sys_file_setattr
470 common listns sys_listns
471 common rseq_slice_yield sys_rseq_slice_yield
+472 common sframe_register sys_sframe_register
+473 common sframe_unregister sys_sframe_unregister
--
2.53.0
