user/sven/linux.git/kernel/sys.c, branch v3.4.85

reboot: rigrate shutdown/reboot to boot cpu

2013-06-20T18:58:45Z

commit cf7df378aa4ff7da3a44769b7ff6e9eef1a9f3db upstream. We recently noticed that reboot of a 1024 cpu machine takes approx 16 minutes of just stopping the cpus. The slowdown was tracked to commit f96972f2dc63 ("kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()"). The current implementation does all the work of hot removing the cpus before halting the system. We are switching to just migrating to the boot cpu and then continuing with shutdown/reboot. This also has the effect of not breaking x86's command line parameter for specifying the reboot cpu. Note, this code was shamelessly copied from arch/x86/kernel/reboot.c with bits removed pertaining to the reboot_cpu command line parameter. Signed-off-by: Robin Holt Tested-by: Shawn Guo Cc: "Srivatsa S. Bhat" Cc: H. Peter Anvin Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Russ Anderson Cc: Robin Holt Cc: Russell King Cc: Guan Xuetao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()

2013-04-17T04:27:26Z

commit 6f389a8f1dd22a24f3d9afc2812b30d639e94625 upstream. As commit 40dc166c (PM / Core: Introduce struct syscore_ops for core subsystems PM) say, syscore_ops operations should be carried with one CPU on-line and interrupts disabled. However, after commit f96972f2d (kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()), syscore_shutdown() is called before disable_nonboot_cpus(), so break the rules. We have a MIPS machine with a 8259A PIC, and there is an external timer (HPET) linked at 8259A. Since 8259A has been shutdown too early (by syscore_shutdown()), disable_nonboot_cpus() runs without timer interrupt, so it hangs and reboot fails. This patch call syscore_shutdown() a little later (after disable_nonboot_cpus()) to avoid reboot failure, this is the same way as poweroff does. For consistency, add disable_nonboot_cpus() to kernel_halt(). Signed-off-by: Huacai Chen Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

use clamp_t in UNAME26 fix

2012-10-28T17:14:13Z

commit 31fd84b95eb211d5db460a1dda85e004800a7b52 upstream. The min/max call needed to have explicit types on some architectures (e.g. mn10300). Use clamp_t instead to avoid the warning: kernel/sys.c: In function 'override_release': kernel/sys.c:1287:10: warning: comparison of distinct pointer types lacks a cast [enabled by default] Reported-by: Fengguang Wu Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

kernel/sys.c: fix stack memory content leak via UNAME26

2012-10-28T17:14:13Z

commit 2702b1526c7278c4d65d78de209a465d4de2885e upstream. Calling uname() with the UNAME26 personality set allows a leak of kernel stack contents. This fixes it by defensively calculating the length of copy_to_user() call, making the len argument unsigned, and initializing the stack buffer to zero (now technically unneeded, but hey, overkill). CVE-2012-0957 Reported-by: PaX Team Signed-off-by: Kees Cook Cc: Andi Kleen Cc: PaX Team Cc: Brad Spengler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()

2012-10-12T20:38:38Z

commit f96972f2dc6365421cf2366ebd61ee4cf060c8d5 upstream. As kernel_power_off() calls disable_nonboot_cpus(), we may also want to have kernel_restart() call disable_nonboot_cpus(). Doing so can help machines that require boot cpu be the last alive cpu during reboot to survive with kernel restart. This fixes one reboot issue seen on imx6q (Cortex-A9 Quad). The machine requires that the restart routine be run on the primary cpu rather than secondary ones. Otherwise, the secondary core running the restart routine will fail to come to online after reboot. Signed-off-by: Shawn Guo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

pidns: add reboot_pid_ns() to handle the reboot syscall

2012-03-29T00:14:36Z

In the case of a child pid namespace, rebooting the system does not really makes sense. When the pid namespace is used in conjunction with the other namespaces in order to create a linux container, the reboot syscall leads to some problems. A container can reboot the host. That can be fixed by dropping the sys_reboot capability but we are unable to correctly to poweroff/ halt/reboot a container and the container stays stuck at the shutdown time with the container's init process waiting indefinitively. After several attempts, no solution from userspace was found to reliabily handle the shutdown from a container. This patch propose to make the init process of the child pid namespace to exit with a signal status set to : SIGINT if the child pid namespace called "halt/poweroff" and SIGHUP if the child pid namespace called "reboot". When the reboot syscall is called and we are not in the initial pid namespace, we kill the pid namespace for "HALT", "POWEROFF", "RESTART", and "RESTART2". Otherwise we return EINVAL. Returning EINVAL is also an easy way to check if this feature is supported by the kernel when invoking another 'reboot' option like CAD. By this way the parent process of the child pid namespace knows if it rebooted or not and can take the right decision. Test case: ========== #include #include #include #include #include #include #include #include #include static int do_reboot(void *arg) { int *cmd = arg; if (reboot(*cmd)) printf("failed to reboot(%d): %m\n", *cmd); } int test_reboot(int cmd, int sig) { long stack_size = 4096; void *stack = alloca(stack_size) + stack_size; int status; pid_t ret; ret = clone(do_reboot, stack, CLONE_NEWPID | SIGCHLD, &cmd); if (ret < 0) { printf("failed to clone: %m\n"); return -1; } if (wait(&status) < 0) { printf("unexpected wait error: %m\n"); return -1; } if (!WIFSIGNALED(status)) { printf("child process exited but was not signaled\n"); return -1; } if (WTERMSIG(status) != sig) { printf("signal termination is not the one expected\n"); return -1; } return 0; } int main(int argc, char *argv[]) { int status; status = test_reboot(LINUX_REBOOT_CMD_RESTART, SIGHUP); if (status < 0) return 1; printf("reboot(LINUX_REBOOT_CMD_RESTART) succeed\n"); status = test_reboot(LINUX_REBOOT_CMD_RESTART2, SIGHUP); if (status < 0) return 1; printf("reboot(LINUX_REBOOT_CMD_RESTART2) succeed\n"); status = test_reboot(LINUX_REBOOT_CMD_HALT, SIGINT); if (status < 0) return 1; printf("reboot(LINUX_REBOOT_CMD_HALT) succeed\n"); status = test_reboot(LINUX_REBOOT_CMD_POWER_OFF, SIGINT); if (status < 0) return 1; printf("reboot(LINUX_REBOOT_CMD_POWERR_OFF) succeed\n"); status = test_reboot(LINUX_REBOOT_CMD_CAD_ON, -1); if (status >= 0) { printf("reboot(LINUX_REBOOT_CMD_CAD_ON) should have failed\n"); return 1; } printf("reboot(LINUX_REBOOT_CMD_CAD_ON) has failed as expected\n"); return 0; } [akpm@linux-foundation.org: tweak and add comments] [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Daniel Lezcano Acked-by: Serge Hallyn Tested-by: Serge Hallyn Reviewed-by: Oleg Nesterov Cc: Michael Kerrisk Cc: "Eric W. Biederman" Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

prctl: add PR_{SET,GET}_CHILD_SUBREAPER to allow simple process supervision

2012-03-23T23:58:32Z

Userspace service managers/supervisors need to track their started services. Many services daemonize by double-forking and get implicitly re-parented to PID 1. The service manager will no longer be able to receive the SIGCHLD signals for them, and is no longer in charge of reaping the children with wait(). All information about the children is lost at the moment PID 1 cleans up the re-parented processes. With this prctl, a service manager process can mark itself as a sort of 'sub-init', able to stay as the parent for all orphaned processes created by the started services. All SIGCHLD signals will be delivered to the service manager. Receiving SIGCHLD and doing wait() is in cases of a service-manager much preferred over any possible asynchronous notification about specific PIDs, because the service manager has full access to the child process data in /proc and the PID can not be re-used until the wait(), the service-manager itself is in charge of, has happened. As a side effect, the relevant parent PID information does not get lost by a double-fork, which results in a more elaborate process tree and 'ps' output: before: # ps afx 253 ? Ss 0:00 /bin/dbus-daemon --system --nofork 294 ? Sl 0:00 /usr/libexec/polkit-1/polkitd 328 ? S 0:00 /usr/sbin/modem-manager 608 ? Sl 0:00 /usr/libexec/colord 658 ? Sl 0:00 /usr/libexec/upowerd 819 ? Sl 0:00 /usr/libexec/imsettings-daemon 916 ? Sl 0:00 /usr/libexec/udisks-daemon 917 ? S 0:00 \_ udisks-daemon: not polling any devices after: # ps afx 294 ? Ss 0:00 /bin/dbus-daemon --system --nofork 426 ? Sl 0:00 \_ /usr/libexec/polkit-1/polkitd 449 ? S 0:00 \_ /usr/sbin/modem-manager 635 ? Sl 0:00 \_ /usr/libexec/colord 705 ? Sl 0:00 \_ /usr/libexec/upowerd 959 ? Sl 0:00 \_ /usr/libexec/udisks-daemon 960 ? S 0:00 | \_ udisks-daemon: not polling any devices 977 ? Sl 0:00 \_ /usr/libexec/packagekitd This prctl is orthogonal to PID namespaces. PID namespaces are isolated from each other, while a service management process usually requires the services to live in the same namespace, to be able to talk to each other. Users of this will be the systemd per-user instance, which provides init-like functionality for the user's login session and D-Bus, which activates bus services on-demand. Both need init-like capabilities to be able to properly keep track of the services they start. Many thanks to Oleg for several rounds of review and insights. [akpm@linux-foundation.org: fix comment layout and spelling] [akpm@linux-foundation.org: add lengthy code comment from Oleg] Reviewed-by: Oleg Nesterov Signed-off-by: Lennart Poettering Signed-off-by: Kay Sievers Acked-by: Valdis Kletnieks Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

prctl: use CAP_SYS_RESOURCE for PR_SET_MM option

2012-03-16T00:03:03Z

CAP_SYS_ADMIN is already overloaded left and right, so to have more fine-grained access control use CAP_SYS_RESOURCE here. The CAP_SYS_RESOUCE is chosen because this prctl option allows a current process to adjust some fields of memory map descriptor which rather represents what the process owns: pointers to code, data, stack segments, command line, auxiliary vector data and etc. Suggested-by: Michael Kerrisk Acked-by: Kees Cook Acked-by: Michael Kerrisk Cc: Pavel Emelyanov Cc: Tejun Heo Cc: Oleg Nesterov Cc: Paul Bolle Cc: KOSAKI Motohiro Signed-off-by: Cyrill Gorcunov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

c/r: prctl: add PR_SET_MM codes to set up mm_struct entries

2012-01-13T04:13:13Z

When we restore a task we need to set up text, data and data heap sizes from userspace to the values a task had at checkpoint time. This patch adds auxilary prctl codes for that. While most of them have a statistical nature (their values are involved into calculation of /proc//statm output) the start_brk and brk values are used to compute an allowed size of program data segment expansion. Which means an arbitrary changes of this values might be dangerous operation. So to restrict access the following requirements applied to prctl calls: - The process has to have CAP_SYS_ADMIN capability granted. - For all opcodes except start_brk/brk members an appropriate VMA area must exist and should fit certain VMA flags, such as: - code segment must be executable but not writable; - data segment must not be executable. start_brk/brk values must not intersect with data segment and must not exceed RLIMIT_DATA resource limit. Still the main guard is CAP_SYS_ADMIN capability check. Note the kernel should be compiled with CONFIG_CHECKPOINT_RESTORE support otherwise these prctl calls will return -EINVAL. [akpm@linux-foundation.org: cache current->mm in a local, saving 200 bytes text] Signed-off-by: Cyrill Gorcunov Reviewed-by: Kees Cook Cc: Tejun Heo Cc: Andrew Vagin Cc: Serge Hallyn Cc: Pavel Emelyanov Cc: Vasiliy Kulikov Cc: KAMEZAWA Hiroyuki Cc: Michael Kerrisk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[S390] cputime: add sparse checking and cleanup

2011-12-15T13:56:19Z

Make cputime_t and cputime64_t nocast to enable sparse checking to detect incorrect use of cputime. Drop the cputime macros for simple scalar operations. The conversion macros are still needed. Signed-off-by: Martin Schwidefsky