- Linux-kselftest-mirror - lists.linaro.org

by Christian Brauner

This adds the close_range() syscall. It allows to efficiently close a range of file descriptors up to all file descriptors of a calling task. The syscall came up in a recent discussion around the new mount API and making new file descriptor types cloexec by default. During this discussion, Al suggested the close_range() syscall (cf. [1]). Note, a syscall in this manner has been requested by various people over time. First, it helps to close all file descriptors of an exec()ing task. This can be done safely via (quoting Al's example from [1] verbatim): /* that exec is sensitive */ unshare(CLONE_FILES); /* we don't want anything past stderr here */ close_range(3, ~0U); execve(....); The code snippet above is one way of working around the problem that file descriptors are not cloexec by default. This is aggravated by the fact that we can't just switch them over without massively regressing userspace. For a whole class of programs having an in-kernel method of closing all file descriptors is very helpful (e.g. demons, service managers, programming language standard libraries, container managers etc.). (Please note, unshare(CLONE_FILES) should only be needed if the calling task is multi-threaded and shares the file descriptor table with another thread in which case two threads could race with one thread allocating file descriptors and the other one closing them via close_range(). For the general case close_range() before the execve() is sufficient.) Second, it allows userspace to avoid implementing closing all file descriptors by parsing through /proc/<pid>/fd/* and calling close() on each file descriptor. From looking at various large(ish) userspace code bases this or similar patterns are very common in: - service managers (cf. [4]) - libcs (cf. [6]) - container runtimes (cf. [5]) - programming language runtimes/standard libraries - Python (cf. [2]) - Rust (cf. [7], [8]) As Dmitry pointed out there's even a long-standing glibc bug about missing kernel support for this task (cf. [3]). In addition, the syscall will also work for tasks that do not have procfs mounted and on kernels that do not have procfs support compiled in. In such situations the only way to make sure that all file descriptors are closed is to call close() on each file descriptor up to UINT_MAX or RLIMIT_NOFILE, OPEN_MAX trickery (cf. comment [8] on Rust). The performance is striking. For good measure, comparing the following simple close_all_fds() userspace implementation that is essentially just glibc's version in [6]: static int close_all_fds(void) { int dir_fd; DIR *dir; struct dirent *direntp; dir = opendir("/proc/self/fd"); if (!dir) return -1; dir_fd = dirfd(dir); while ((direntp = readdir(dir))) { int fd; if (strcmp(direntp->d_name, ".") == 0) continue; if (strcmp(direntp->d_name, "..") == 0) continue; fd = atoi(direntp->d_name); if (fd == dir_fd || fd == 0 || fd == 1 || fd == 2) continue; close(fd); } closedir(dir); return 0; } to close_range() yields: 1. closing 4 open files: - close_all_fds(): ~280 us - close_range(): ~24 us 2. closing 1000 open files: - close_all_fds(): ~5000 us - close_range(): ~800 us close_range() is designed to allow for some flexibility. Specifically, it does not simply always close all open file descriptors of a task. Instead, callers can specify an upper bound. This is e.g. useful for scenarios where specific file descriptors are created with well-known numbers that are supposed to be excluded from getting closed. For extra paranoia close_range() comes with a flags argument. This can e.g. be used to implement extension. Once can imagine userspace wanting to stop at the first error instead of ignoring errors under certain circumstances. There might be other valid ideas in the future. In any case, a flag argument doesn't hurt and keeps us on the safe side. >From an implementation side this is kept rather dumb. It saw some input from David and Jann but all nonsense is obviously my own! - Errors to close file descriptors are currently ignored. (Could be changed by setting a flag in the future if needed.) - __close_range() is a rather simplistic wrapper around __close_fd(). My reasoning behind this is based on the nature of how __close_fd() needs to release an fd. But maybe I misunderstood specifics: We take the files_lock and rcu-dereference the fdtable of the calling task, we find the entry in the fdtable, get the file and need to release files_lock before calling filp_close(). In the meantime the fdtable might have been altered so we can't just retake the spinlock and keep the old rcu-reference of the fdtable around. Instead we need to grab a fresh reference to the fdtable. If my reasoning is correct then there's really no point in fancyfying __close_range(): We just need to rcu-dereference the fdtable of the calling task once to cap the max_fd value correctly and then go on calling __close_fd() in a loop. /* References */ [1]: https://lore.kernel.org/lkml/20190516165021.GD17978@ZenIV.linux.org.uk/ [2]: https://github.com/python/cpython/blob/9e4f2f3a6b8ee995c365e86d976937c141d8… [3]: https://sourceware.org/bugzilla/show_bug.cgi?id=10353#c7 [4]: https://github.com/systemd/systemd/blob/5238e9575906297608ff802a27e2ff9effa… [5]: https://github.com/lxc/lxc/blob/ddf4b77e11a4d08f09b7b9cd13e593f8c047edc5/sr… [6]: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/gr… Note that this is an internal implementation that is not exported. Currently, libc seems to not provide an exported version of this because of missing kernel support to do this. [7]: https://github.com/rust-lang/rust/issues/12148 [8]: https://github.com/rust-lang/rust/blob/5f47c0613ed4eb46fca3633c1297364c09e5… Rust's solution is slightly different but is equally unperformant. Rust calls getdtablesize() which is a glibc library function that simply returns the current RLIMIT_NOFILE or OPEN_MAX values. Rust then goes on to call close() on each fd. That's obviously overkill for most tasks. Rarely, tasks - especially non-demons - hit RLIMIT_NOFILE or OPEN_MAX. Let's be nice and assume an unprivileged user with RLIMIT_NOFILE set to 1024. Even in this case, there's a very high chance that in the common case Rust is calling the close() syscall 1021 times pointlessly if the task just has 0, 1, and 2 open. Suggested-by: Al Viro <viro(a)zeniv.linux.org.uk> Signed-off-by: Christian Brauner <christian(a)brauner.io> Cc: Arnd Bergmann <arnd(a)arndb.de> Cc: Jann Horn <jannh(a)google.com> Cc: David Howells <dhowells(a)redhat.com> Cc: Dmitry V. Levin <ldv(a)altlinux.org> Cc: Oleg Nesterov <oleg(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Florian Weimer <fweimer(a)redhat.com> Cc: linux-api(a)vger.kernel.org --- v1: - Linus Torvalds <torvalds(a)linux-foundation.org>: - add cond_resched() to yield cpu when closing a lot of file descriptors - Al Viro <viro(a)zeniv.linux.org.uk>: - add cond_resched() to yield cpu when closing a lot of file descriptors --- arch/alpha/kernel/syscalls/syscall.tbl | 1 + arch/arm/tools/syscall.tbl | 1 + arch/arm64/include/asm/unistd32.h | 2 + arch/ia64/kernel/syscalls/syscall.tbl | 1 + arch/m68k/kernel/syscalls/syscall.tbl | 1 + arch/microblaze/kernel/syscalls/syscall.tbl | 1 + arch/mips/kernel/syscalls/syscall_n32.tbl | 1 + arch/mips/kernel/syscalls/syscall_n64.tbl | 1 + arch/mips/kernel/syscalls/syscall_o32.tbl | 1 + arch/parisc/kernel/syscalls/syscall.tbl | 1 + arch/powerpc/kernel/syscalls/syscall.tbl | 1 + arch/s390/kernel/syscalls/syscall.tbl | 1 + arch/sh/kernel/syscalls/syscall.tbl | 1 + arch/sparc/kernel/syscalls/syscall.tbl | 1 + arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + arch/xtensa/kernel/syscalls/syscall.tbl | 1 + fs/file.c | 63 ++++++++++++++++++--- fs/open.c | 20 +++++++ include/linux/fdtable.h | 2 + include/linux/syscalls.h | 2 + include/uapi/asm-generic/unistd.h | 4 +- 22 files changed, 100 insertions(+), 9 deletions(-) diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl index 9e7704e44f6d..b55d93af8096 100644 --- a/arch/alpha/kernel/syscalls/syscall.tbl +++ b/arch/alpha/kernel/syscalls/syscall.tbl @@ -473,3 +473,4 @@ 541 common fsconfig sys_fsconfig 542 common fsmount sys_fsmount 543 common fspick sys_fspick +545 common close_range sys_close_range diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl index aaf479a9e92d..0125c97c75dd 100644 --- a/arch/arm/tools/syscall.tbl +++ b/arch/arm/tools/syscall.tbl @@ -447,3 +447,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h index c39e90600bb3..9a3270d29b42 100644 --- a/arch/arm64/include/asm/unistd32.h +++ b/arch/arm64/include/asm/unistd32.h @@ -886,6 +886,8 @@ __SYSCALL(__NR_fsconfig, sys_fsconfig) __SYSCALL(__NR_fsmount, sys_fsmount) #define __NR_fspick 433 __SYSCALL(__NR_fspick, sys_fspick) +#define __NR_close_range 435 +__SYSCALL(__NR_close_range, sys_close_range) /* * Please add new compat syscalls above this comment and update diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl index e01df3f2f80d..1a90b464e96f 100644 --- a/arch/ia64/kernel/syscalls/syscall.tbl +++ b/arch/ia64/kernel/syscalls/syscall.tbl @@ -354,3 +354,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl index 7e3d0734b2f3..2dee2050f9ef 100644 --- a/arch/m68k/kernel/syscalls/syscall.tbl +++ b/arch/m68k/kernel/syscalls/syscall.tbl @@ -433,3 +433,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl index 26339e417695..923ef69e5a76 100644 --- a/arch/microblaze/kernel/syscalls/syscall.tbl +++ b/arch/microblaze/kernel/syscalls/syscall.tbl @@ -439,3 +439,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl index 0e2dd68ade57..967ed9de51cd 100644 --- a/arch/mips/kernel/syscalls/syscall_n32.tbl +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl @@ -372,3 +372,4 @@ 431 n32 fsconfig sys_fsconfig 432 n32 fsmount sys_fsmount 433 n32 fspick sys_fspick +435 n32 close_range sys_close_range diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl index 5eebfa0d155c..71de731102b1 100644 --- a/arch/mips/kernel/syscalls/syscall_n64.tbl +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl @@ -348,3 +348,4 @@ 431 n64 fsconfig sys_fsconfig 432 n64 fsmount sys_fsmount 433 n64 fspick sys_fspick +435 n64 close_range sys_close_range diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl index 3cc1374e02d0..5a325ab29f88 100644 --- a/arch/mips/kernel/syscalls/syscall_o32.tbl +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl @@ -421,3 +421,4 @@ 431 o32 fsconfig sys_fsconfig 432 o32 fsmount sys_fsmount 433 o32 fspick sys_fspick +435 o32 close_range sys_close_range diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl index c9e377d59232..dcc0a0879139 100644 --- a/arch/parisc/kernel/syscalls/syscall.tbl +++ b/arch/parisc/kernel/syscalls/syscall.tbl @@ -430,3 +430,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl index 103655d84b4b..ba2c1f078cbd 100644 --- a/arch/powerpc/kernel/syscalls/syscall.tbl +++ b/arch/powerpc/kernel/syscalls/syscall.tbl @@ -515,3 +515,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl index e822b2964a83..d7c9043d2902 100644 --- a/arch/s390/kernel/syscalls/syscall.tbl +++ b/arch/s390/kernel/syscalls/syscall.tbl @@ -436,3 +436,4 @@ 431 common fsconfig sys_fsconfig sys_fsconfig 432 common fsmount sys_fsmount sys_fsmount 433 common fspick sys_fspick sys_fspick +435 common close_range sys_close_range sys_close_range diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl index 016a727d4357..9b5e6bf0ce32 100644 --- a/arch/sh/kernel/syscalls/syscall.tbl +++ b/arch/sh/kernel/syscalls/syscall.tbl @@ -436,3 +436,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl index e047480b1605..8c674a1e0072 100644 --- a/arch/sparc/kernel/syscalls/syscall.tbl +++ b/arch/sparc/kernel/syscalls/syscall.tbl @@ -479,3 +479,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index ad968b7bac72..7f7a89a96707 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -438,3 +438,4 @@ 431 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig 432 i386 fsmount sys_fsmount __ia32_sys_fsmount 433 i386 fspick sys_fspick __ia32_sys_fspick +435 i386 close_range sys_close_range __ia32_sys_close_range diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index b4e6f9e6204a..0f7d47ae921c 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -355,6 +355,7 @@ 431 common fsconfig __x64_sys_fsconfig 432 common fsmount __x64_sys_fsmount 433 common fspick __x64_sys_fspick +435 common close_range __x64_sys_close_range # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl index 5fa0ee1c8e00..b489532265d0 100644 --- a/arch/xtensa/kernel/syscalls/syscall.tbl +++ b/arch/xtensa/kernel/syscalls/syscall.tbl @@ -404,3 +404,4 @@ 431 common fsconfig sys_fsconfig 432 common fsmount sys_fsmount 433 common fspick sys_fspick +435 common close_range sys_close_range diff --git a/fs/file.c b/fs/file.c index 3da91a112bab..54945efa046e 100644 --- a/fs/file.c +++ b/fs/file.c @@ -615,12 +615,9 @@ void fd_install(unsigned int fd, struct file *file) EXPORT_SYMBOL(fd_install); -/* - * The same warnings as for __alloc_fd()/__fd_install() apply here... - */ -int __close_fd(struct files_struct *files, unsigned fd) +static struct file *pick_file(struct files_struct *files, unsigned fd) { - struct file *file; + struct file *file = NULL; struct fdtable *fdt; spin_lock(&files->file_lock); @@ -632,15 +629,65 @@ int __close_fd(struct files_struct *files, unsigned fd) goto out_unlock; rcu_assign_pointer(fdt->fd[fd], NULL); __put_unused_fd(files, fd); - spin_unlock(&files->file_lock); - return filp_close(file, files); out_unlock: spin_unlock(&files->file_lock); - return -EBADF; + return file; +} + +/* + * The same warnings as for __alloc_fd()/__fd_install() apply here... + */ +int __close_fd(struct files_struct *files, unsigned fd) +{ + struct file *file; + + file = pick_file(files, fd); + if (!file) + return -EBADF; + + return filp_close(file, files); } EXPORT_SYMBOL(__close_fd); /* for ksys_close() */ +/** + * __close_range() - Close all file descriptors in a given range. + * + * @fd: starting file descriptor to close + * @max_fd: last file descriptor to close + * + * This closes a range of file descriptors. All file descriptors + * from @fd up to and including @max_fd are closed. + */ +int __close_range(struct files_struct *files, unsigned fd, unsigned max_fd) +{ + unsigned int cur_max; + + if (fd > max_fd) + return -EINVAL; + + rcu_read_lock(); + cur_max = files_fdtable(files)->max_fds; + rcu_read_unlock(); + + /* cap to last valid index into fdtable */ + if (max_fd >= cur_max) + max_fd = cur_max - 1; + + while (fd <= max_fd) { + struct file *file; + + file = pick_file(files, fd++); + if (!file) + continue; + + filp_close(file, files); + cond_resched(); + } + + return 0; +} + /* * variant of __close_fd that gets a ref on the file for later fput */ diff --git a/fs/open.c b/fs/open.c index 9c7d724a6f67..c7baaee7aa47 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1174,6 +1174,26 @@ SYSCALL_DEFINE1(close, unsigned int, fd) return retval; } +/** + * close_range() - Close all file descriptors in a given range. + * + * @fd: starting file descriptor to close + * @max_fd: last file descriptor to close + * @flags: reserved for future extensions + * + * This closes a range of file descriptors. All file descriptors + * from @fd up to and including @max_fd are closed. + * Currently, errors to close a given file descriptor are ignored. + */ +SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd, + unsigned int, flags) +{ + if (flags) + return -EINVAL; + + return __close_range(current->files, fd, max_fd); +} + /* * This routine simulates a hangup on the tty, to arrange that users * are given clean terminals at login time. diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h index f07c55ea0c22..fcd07181a365 100644 --- a/include/linux/fdtable.h +++ b/include/linux/fdtable.h @@ -121,6 +121,8 @@ extern void __fd_install(struct files_struct *files, unsigned int fd, struct file *file); extern int __close_fd(struct files_struct *files, unsigned int fd); +extern int __close_range(struct files_struct *files, unsigned int fd, + unsigned int max_fd); extern int __close_fd_get_file(unsigned int fd, struct file **res); extern struct kmem_cache *files_cachep; diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index e2870fe1be5b..c0189e223255 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -441,6 +441,8 @@ asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group); asmlinkage long sys_openat(int dfd, const char __user *filename, int flags, umode_t mode); asmlinkage long sys_close(unsigned int fd); +asmlinkage long sys_close_range(unsigned int fd, unsigned int max_fd, + unsigned int flags); asmlinkage long sys_vhangup(void); /* fs/pipe.c */ diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index a87904daf103..3f36c8745d24 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -844,9 +844,11 @@ __SYSCALL(__NR_fsconfig, sys_fsconfig) __SYSCALL(__NR_fsmount, sys_fsmount) #define __NR_fspick 433 __SYSCALL(__NR_fspick, sys_fspick) +#define __NR_close_range 435 +__SYSCALL(__NR_close_range, sys_close_range) #undef __NR_syscalls -#define __NR_syscalls 434 +#define __NR_syscalls 436 /* * 32 bit systems traditionally used different -- 2.21.0

6 years, 1 month

6
14
0 0

[PATCH selftests 0/2] Add checkbashisms meta-testcase

by Masami Hiramatsu

Hi, Here are patches for making sure the ftracetest testcases are checkbashisms clean. This actually needs a patch from Juerg, "selftests/ftrace: Make the coloring POSIX compliant" to complete the work. http://lkml.kernel.org/r/20190220161333.28109-1-juergh@canonical.com (Note that this is still under development) So as Juerg pointed, recently ftracetest becomes not POSIX compliant, and such kind of issues happened repeatedly. To avoid those anymore, I decided to introduce a testcase which runs checkbasisms on ftracetest and its testcases. I think this can help us to find out whether it was written in a way out of POSIX. Thank you, --- Masami Hiramatsu (2): selftests/ftrace: Make a script checkbashisms clean selftests/ftrace: Add checkbashisms meta-testcase tools/testing/selftests/ftrace/ftracetest | 1 + .../ftrace/test.d/kprobe/kprobe_ftrace.tc | 2 +- .../selftests/ftrace/test.d/selftest/bashisms.tc | 21 ++++++++++++++++++++ 3 files changed, 23 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/ftrace/test.d/selftest/bashisms.tc -- Masami Hiramatsu (Linaro) <mhiramat(a)kernel.org>

6 years, 1 month

3
5
0 0

[PATCH] selftests: add missing include linux/sockios

by Alakesh Haloi

Including <linux/sockios.h> fixes the following compiler warning timestamping.c: In function ‘printpacket’: timestamping.c:261:19: error: ‘SIOCGSTAMP’ undeclared (first use in this function); did you mean ‘SIOCGSTAMPNS’? if (ioctl(sock, SIOCGSTAMP, &tv)) ^~~~~~~~~~ SIOCGSTAMPNS Signed-off-by: Alakesh Haloi <alakesh.haloi(a)gmail.com> --- tools/testing/selftests/networking/timestamping/timestamping.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/networking/timestamping/timestamping.c b/tools/testing/selftests/networking/timestamping/timestamping.c index 5cdfd743447b..62f03bcc9432 100644 --- a/tools/testing/selftests/networking/timestamping/timestamping.c +++ b/tools/testing/selftests/networking/timestamping/timestamping.c @@ -44,6 +44,7 @@ #include <asm/types.h> #include <linux/net_tstamp.h> #include <linux/errqueue.h> +#include <linux/sockios.h> #ifndef SO_TIMESTAMPING # define SO_TIMESTAMPING 37 -- 2.17.1

6 years, 1 month

1
0
0 0

[PATCH] selftests: kselftest: fix function return type

by Alakesh Haloi

ksft_test_num function returns sum of unsigned ints and hence should return unsigned int. This fixes the following compiler warning In file included from sync_test.c:37:0: ../kselftest.h: In function ‘ksft_print_cnts’: ../kselftest.h:73:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ksft_plan != ksft_test_num()) ^~ Signed-off-by: Alakesh Haloi <alakesh.haloi(a)gmail.com> --- tools/testing/selftests/kselftest.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h index ec15c4f6af55..5a98c80e079e 100644 --- a/tools/testing/selftests/kselftest.h +++ b/tools/testing/selftests/kselftest.h @@ -35,7 +35,7 @@ struct ksft_count { static struct ksft_count ksft_cnt; static unsigned int ksft_plan; -static inline int ksft_test_num(void) +static inline unsigned int ksft_test_num(void) { return ksft_cnt.ksft_pass + ksft_cnt.ksft_fail + ksft_cnt.ksft_xfail + ksft_cnt.ksft_xpass + -- 2.17.1

6 years, 1 month

1
0
0 0

[PATCH 0/2] kselftest: fix rtctest timeout

by Alexandre Belloni

Hi, Commit a745f7af3cbd ("selftests/harness: Add 30 second timeout per test") wrongly assumed that no individual test would run for more than 30 seconds and this silently broke rtctest. Please consider the following patches as fixes for v5.2 to avoid having any non working release. Thanks, Alexandre Belloni (2): selftests/harness: Allow test to configure timeout selftests: rtc: rtctest: specify timeouts tools/testing/selftests/kselftest_harness.h | 17 ++++++++++++----- tools/testing/selftests/rtc/rtctest.c | 6 +++--- 2 files changed, 15 insertions(+), 8 deletions(-) -- 2.21.0

6 years, 1 month

3
6
0 0

[PATCH 5.1 075/122] ftrace/x86_64: Emulate call function while updating in breakpoint handler

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 9e298e8604088a600d8100a111a532a9d342af09 upstream. Nicolai Stange discovered[1] that if live kernel patching is enabled, and the function tracer started tracing the same function that was patched, the conversion of the fentry call site during the translation of going from calling the live kernel patch trampoline to the iterator trampoline, would have as slight window where it didn't call anything. As live kernel patching depends on ftrace to always call its code (to prevent the function being traced from being called, as it will redirect it). This small window would allow the old buggy function to be called, and this can cause undesirable results. Nicolai submitted new patches[2] but these were controversial. As this is similar to the static call emulation issues that came up a while ago[3]. But after some debate[4][5] adding a gap in the stack when entering the breakpoint handler allows for pushing the return address onto the stack to easily emulate a call. [1] http://lkml.kernel.org/r/20180726104029.7736-1-nstange@suse.de [2] http://lkml.kernel.org/r/20190427100639.15074-1-nstange@suse.de [3] http://lkml.kernel.org/r/3cf04e113d71c9f8e4be95fb84a510f085aa4afa.154171145… [4] http://lkml.kernel.org/r/CAHk-=wh5OpheSU8Em_Q3Hg8qw_JtoijxOdPtHru6d+5K8TWM=… [5] http://lkml.kernel.org/r/CAHk-=wjvQxY4DvPrJ6haPgAa6b906h=MwZXO6G8OtiTGe=N7_… [ Live kernel patching is not implemented on x86_32, thus the emulate calls are only for x86_64. ] Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Nicolai Stange <nstange(a)suse.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: the arch/x86 maintainers <x86(a)kernel.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Jiri Kosina <jikos(a)kernel.org> Cc: Miroslav Benes <mbenes(a)suse.cz> Cc: Petr Mladek <pmladek(a)suse.com> Cc: Joe Lawrence <joe.lawrence(a)redhat.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> Cc: Mimi Zohar <zohar(a)linux.ibm.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Nick Desaulniers <ndesaulniers(a)google.com> Cc: Nayna Jain <nayna(a)linux.ibm.com> Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com> Cc: Joerg Roedel <jroedel(a)suse.de> Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org> Cc: stable(a)vger.kernel.org Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching") Tested-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> [ Changed to only implement emulated calls for x86_64 ] Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/ftrace.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -29,6 +29,7 @@ #include <asm/kprobes.h> #include <asm/ftrace.h> #include <asm/nops.h> +#include <asm/text-patching.h> #ifdef CONFIG_DYNAMIC_FTRACE @@ -231,6 +232,7 @@ int ftrace_modify_call(struct dyn_ftrace } static unsigned long ftrace_update_func; +static unsigned long ftrace_update_func_call; static int update_ftrace_func(unsigned long ip, void *new) { @@ -259,6 +261,8 @@ int ftrace_update_ftrace_func(ftrace_fun unsigned char *new; int ret; + ftrace_update_func_call = (unsigned long)func; + new = ftrace_call_replace(ip, (unsigned long)func); ret = update_ftrace_func(ip, new); @@ -294,13 +298,28 @@ int ftrace_int3_handler(struct pt_regs * if (WARN_ON_ONCE(!regs)) return 0; - ip = regs->ip - 1; - if (!ftrace_location(ip) && !is_ftrace_caller(ip)) - return 0; + ip = regs->ip - INT3_INSN_SIZE; - regs->ip += MCOUNT_INSN_SIZE - 1; +#ifdef CONFIG_X86_64 + if (ftrace_location(ip)) { + int3_emulate_call(regs, (unsigned long)ftrace_regs_caller); + return 1; + } else if (is_ftrace_caller(ip)) { + if (!ftrace_update_func_call) { + int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); + return 1; + } + int3_emulate_call(regs, ftrace_update_func_call); + return 1; + } +#else + if (ftrace_location(ip) || is_ftrace_caller(ip)) { + int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); + return 1; + } +#endif - return 1; + return 0; } NOKPROBE_SYMBOL(ftrace_int3_handler); @@ -859,6 +878,8 @@ void arch_ftrace_update_trampoline(struc func = ftrace_ops_get_func(ops); + ftrace_update_func_call = (unsigned long)func; + /* Do a safe modify in case the trampoline is executing */ new = ftrace_call_replace(ip, (unsigned long)func); ret = update_ftrace_func(ip, new); @@ -960,6 +981,7 @@ static int ftrace_mod_jmp(unsigned long { unsigned char *new; + ftrace_update_func_call = 0UL; new = ftrace_jmp_replace(ip, (unsigned long)func); return update_ftrace_func(ip, new);

6 years, 1 month

1
0
0 0

[PATCH 5.1 074/122] x86_64: Allow breakpoints to emulate call instructions

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 4b33dadf37666c0860b88f9e52a16d07bf6d0b03 upstream. In order to allow breakpoints to emulate call instructions, they need to push the return address onto the stack. The x86_64 int3 handler adds a small gap to allow the stack to grow some. Use this gap to add the return address to be able to emulate a call instruction at the breakpoint location. These helper functions are added: int3_emulate_jmp(): changes the location of the regs->ip to return there. (The next two are only for x86_64) int3_emulate_push(): to push the address onto the gap in the stack int3_emulate_call(): push the return address and change regs->ip Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Nicolai Stange <nstange(a)suse.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: the arch/x86 maintainers <x86(a)kernel.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Jiri Kosina <jikos(a)kernel.org> Cc: Miroslav Benes <mbenes(a)suse.cz> Cc: Petr Mladek <pmladek(a)suse.com> Cc: Joe Lawrence <joe.lawrence(a)redhat.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> Cc: Mimi Zohar <zohar(a)linux.ibm.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Nick Desaulniers <ndesaulniers(a)google.com> Cc: Nayna Jain <nayna(a)linux.ibm.com> Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com> Cc: Joerg Roedel <jroedel(a)suse.de> Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org> Cc: stable(a)vger.kernel.org Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching") Tested-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> [ Modified to only work for x86_64 and added comment to int3_emulate_push() ] Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/text-patching.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -39,4 +39,32 @@ extern int poke_int3_handler(struct pt_r extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); extern int after_bootmem; +static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) +{ + regs->ip = ip; +} + +#define INT3_INSN_SIZE 1 +#define CALL_INSN_SIZE 5 + +#ifdef CONFIG_X86_64 +static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val) +{ + /* + * The int3 handler in entry_64.S adds a gap between the + * stack where the break point happened, and the saving of + * pt_regs. We can extend the original stack because of + * this gap. See the idtentry macro's create_gap option. + */ + regs->sp -= sizeof(unsigned long); + *(unsigned long *)regs->sp = val; +} + +static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func) +{ + int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); + int3_emulate_jmp(regs, func); +} +#endif + #endif /* _ASM_X86_TEXT_PATCHING_H */

6 years, 1 month

1
0
0 0

[PATCH 5.0 066/139] ftrace/x86_64: Emulate call function while updating in breakpoint handler

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 9e298e8604088a600d8100a111a532a9d342af09 upstream. Nicolai Stange discovered[1] that if live kernel patching is enabled, and the function tracer started tracing the same function that was patched, the conversion of the fentry call site during the translation of going from calling the live kernel patch trampoline to the iterator trampoline, would have as slight window where it didn't call anything. As live kernel patching depends on ftrace to always call its code (to prevent the function being traced from being called, as it will redirect it). This small window would allow the old buggy function to be called, and this can cause undesirable results. Nicolai submitted new patches[2] but these were controversial. As this is similar to the static call emulation issues that came up a while ago[3]. But after some debate[4][5] adding a gap in the stack when entering the breakpoint handler allows for pushing the return address onto the stack to easily emulate a call. [1] http://lkml.kernel.org/r/20180726104029.7736-1-nstange@suse.de [2] http://lkml.kernel.org/r/20190427100639.15074-1-nstange@suse.de [3] http://lkml.kernel.org/r/3cf04e113d71c9f8e4be95fb84a510f085aa4afa.154171145… [4] http://lkml.kernel.org/r/CAHk-=wh5OpheSU8Em_Q3Hg8qw_JtoijxOdPtHru6d+5K8TWM=… [5] http://lkml.kernel.org/r/CAHk-=wjvQxY4DvPrJ6haPgAa6b906h=MwZXO6G8OtiTGe=N7_… [ Live kernel patching is not implemented on x86_32, thus the emulate calls are only for x86_64. ] Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Nicolai Stange <nstange(a)suse.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: the arch/x86 maintainers <x86(a)kernel.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Jiri Kosina <jikos(a)kernel.org> Cc: Miroslav Benes <mbenes(a)suse.cz> Cc: Petr Mladek <pmladek(a)suse.com> Cc: Joe Lawrence <joe.lawrence(a)redhat.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> Cc: Mimi Zohar <zohar(a)linux.ibm.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Nick Desaulniers <ndesaulniers(a)google.com> Cc: Nayna Jain <nayna(a)linux.ibm.com> Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com> Cc: Joerg Roedel <jroedel(a)suse.de> Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org> Cc: stable(a)vger.kernel.org Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching") Tested-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> [ Changed to only implement emulated calls for x86_64 ] Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/ftrace.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -29,6 +29,7 @@ #include <asm/kprobes.h> #include <asm/ftrace.h> #include <asm/nops.h> +#include <asm/text-patching.h> #ifdef CONFIG_DYNAMIC_FTRACE @@ -231,6 +232,7 @@ int ftrace_modify_call(struct dyn_ftrace } static unsigned long ftrace_update_func; +static unsigned long ftrace_update_func_call; static int update_ftrace_func(unsigned long ip, void *new) { @@ -259,6 +261,8 @@ int ftrace_update_ftrace_func(ftrace_fun unsigned char *new; int ret; + ftrace_update_func_call = (unsigned long)func; + new = ftrace_call_replace(ip, (unsigned long)func); ret = update_ftrace_func(ip, new); @@ -294,13 +298,28 @@ int ftrace_int3_handler(struct pt_regs * if (WARN_ON_ONCE(!regs)) return 0; - ip = regs->ip - 1; - if (!ftrace_location(ip) && !is_ftrace_caller(ip)) - return 0; + ip = regs->ip - INT3_INSN_SIZE; - regs->ip += MCOUNT_INSN_SIZE - 1; +#ifdef CONFIG_X86_64 + if (ftrace_location(ip)) { + int3_emulate_call(regs, (unsigned long)ftrace_regs_caller); + return 1; + } else if (is_ftrace_caller(ip)) { + if (!ftrace_update_func_call) { + int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); + return 1; + } + int3_emulate_call(regs, ftrace_update_func_call); + return 1; + } +#else + if (ftrace_location(ip) || is_ftrace_caller(ip)) { + int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); + return 1; + } +#endif - return 1; + return 0; } static int ftrace_write(unsigned long ip, const char *val, int size) @@ -858,6 +877,8 @@ void arch_ftrace_update_trampoline(struc func = ftrace_ops_get_func(ops); + ftrace_update_func_call = (unsigned long)func; + /* Do a safe modify in case the trampoline is executing */ new = ftrace_call_replace(ip, (unsigned long)func); ret = update_ftrace_func(ip, new); @@ -959,6 +980,7 @@ static int ftrace_mod_jmp(unsigned long { unsigned char *new; + ftrace_update_func_call = 0UL; new = ftrace_jmp_replace(ip, (unsigned long)func); return update_ftrace_func(ip, new);

6 years, 1 month

1
0
0 0

[PATCH 5.0 065/139] x86_64: Allow breakpoints to emulate call instructions

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 4b33dadf37666c0860b88f9e52a16d07bf6d0b03 upstream. In order to allow breakpoints to emulate call instructions, they need to push the return address onto the stack. The x86_64 int3 handler adds a small gap to allow the stack to grow some. Use this gap to add the return address to be able to emulate a call instruction at the breakpoint location. These helper functions are added: int3_emulate_jmp(): changes the location of the regs->ip to return there. (The next two are only for x86_64) int3_emulate_push(): to push the address onto the gap in the stack int3_emulate_call(): push the return address and change regs->ip Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Nicolai Stange <nstange(a)suse.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: the arch/x86 maintainers <x86(a)kernel.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Jiri Kosina <jikos(a)kernel.org> Cc: Miroslav Benes <mbenes(a)suse.cz> Cc: Petr Mladek <pmladek(a)suse.com> Cc: Joe Lawrence <joe.lawrence(a)redhat.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> Cc: Mimi Zohar <zohar(a)linux.ibm.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Nick Desaulniers <ndesaulniers(a)google.com> Cc: Nayna Jain <nayna(a)linux.ibm.com> Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com> Cc: Joerg Roedel <jroedel(a)suse.de> Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org> Cc: stable(a)vger.kernel.org Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching") Tested-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> [ Modified to only work for x86_64 and added comment to int3_emulate_push() ] Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/text-patching.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -39,4 +39,32 @@ extern int poke_int3_handler(struct pt_r extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); extern int after_bootmem; +static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) +{ + regs->ip = ip; +} + +#define INT3_INSN_SIZE 1 +#define CALL_INSN_SIZE 5 + +#ifdef CONFIG_X86_64 +static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val) +{ + /* + * The int3 handler in entry_64.S adds a gap between the + * stack where the break point happened, and the saving of + * pt_regs. We can extend the original stack because of + * this gap. See the idtentry macro's create_gap option. + */ + regs->sp -= sizeof(unsigned long); + *(unsigned long *)regs->sp = val; +} + +static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func) +{ + int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); + int3_emulate_jmp(regs, func); +} +#endif + #endif /* _ASM_X86_TEXT_PATCHING_H */

6 years, 1 month

1
0
0 0

[PATCH 4.14 34/77] ftrace/x86_64: Emulate call function while updating in breakpoint handler

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 9e298e8604088a600d8100a111a532a9d342af09 upstream. Nicolai Stange discovered[1] that if live kernel patching is enabled, and the function tracer started tracing the same function that was patched, the conversion of the fentry call site during the translation of going from calling the live kernel patch trampoline to the iterator trampoline, would have as slight window where it didn't call anything. As live kernel patching depends on ftrace to always call its code (to prevent the function being traced from being called, as it will redirect it). This small window would allow the old buggy function to be called, and this can cause undesirable results. Nicolai submitted new patches[2] but these were controversial. As this is similar to the static call emulation issues that came up a while ago[3]. But after some debate[4][5] adding a gap in the stack when entering the breakpoint handler allows for pushing the return address onto the stack to easily emulate a call. [1] http://lkml.kernel.org/r/20180726104029.7736-1-nstange@suse.de [2] http://lkml.kernel.org/r/20190427100639.15074-1-nstange@suse.de [3] http://lkml.kernel.org/r/3cf04e113d71c9f8e4be95fb84a510f085aa4afa.154171145… [4] http://lkml.kernel.org/r/CAHk-=wh5OpheSU8Em_Q3Hg8qw_JtoijxOdPtHru6d+5K8TWM=… [5] http://lkml.kernel.org/r/CAHk-=wjvQxY4DvPrJ6haPgAa6b906h=MwZXO6G8OtiTGe=N7_… [ Live kernel patching is not implemented on x86_32, thus the emulate calls are only for x86_64. ] Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Nicolai Stange <nstange(a)suse.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: the arch/x86 maintainers <x86(a)kernel.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Jiri Kosina <jikos(a)kernel.org> Cc: Miroslav Benes <mbenes(a)suse.cz> Cc: Petr Mladek <pmladek(a)suse.com> Cc: Joe Lawrence <joe.lawrence(a)redhat.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> Cc: Mimi Zohar <zohar(a)linux.ibm.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Nick Desaulniers <ndesaulniers(a)google.com> Cc: Nayna Jain <nayna(a)linux.ibm.com> Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com> Cc: Joerg Roedel <jroedel(a)suse.de> Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org> Cc: stable(a)vger.kernel.org Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching") Tested-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Nicolai Stange <nstange(a)suse.de> Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> [ Changed to only implement emulated calls for x86_64 ] Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/ftrace.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -30,6 +30,7 @@ #include <asm/sections.h> #include <asm/ftrace.h> #include <asm/nops.h> +#include <asm/text-patching.h> #ifdef CONFIG_DYNAMIC_FTRACE @@ -229,6 +230,7 @@ int ftrace_modify_call(struct dyn_ftrace } static unsigned long ftrace_update_func; +static unsigned long ftrace_update_func_call; static int update_ftrace_func(unsigned long ip, void *new) { @@ -257,6 +259,8 @@ int ftrace_update_ftrace_func(ftrace_fun unsigned char *new; int ret; + ftrace_update_func_call = (unsigned long)func; + new = ftrace_call_replace(ip, (unsigned long)func); ret = update_ftrace_func(ip, new); @@ -292,13 +296,28 @@ int ftrace_int3_handler(struct pt_regs * if (WARN_ON_ONCE(!regs)) return 0; - ip = regs->ip - 1; - if (!ftrace_location(ip) && !is_ftrace_caller(ip)) - return 0; + ip = regs->ip - INT3_INSN_SIZE; - regs->ip += MCOUNT_INSN_SIZE - 1; +#ifdef CONFIG_X86_64 + if (ftrace_location(ip)) { + int3_emulate_call(regs, (unsigned long)ftrace_regs_caller); + return 1; + } else if (is_ftrace_caller(ip)) { + if (!ftrace_update_func_call) { + int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); + return 1; + } + int3_emulate_call(regs, ftrace_update_func_call); + return 1; + } +#else + if (ftrace_location(ip) || is_ftrace_caller(ip)) { + int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); + return 1; + } +#endif - return 1; + return 0; } static int ftrace_write(unsigned long ip, const char *val, int size) @@ -869,6 +888,8 @@ void arch_ftrace_update_trampoline(struc func = ftrace_ops_get_func(ops); + ftrace_update_func_call = (unsigned long)func; + /* Do a safe modify in case the trampoline is executing */ new = ftrace_call_replace(ip, (unsigned long)func); ret = update_ftrace_func(ip, new); @@ -965,6 +986,7 @@ static int ftrace_mod_jmp(unsigned long { unsigned char *new; + ftrace_update_func_call = 0UL; new = ftrace_jmp_replace(ip, (unsigned long)func); return update_ftrace_func(ip, new);

6 years, 1 month

1
0
0 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

Linux-kselftest-mirror