| Message ID | 20200511135918.8203-6-andrzej.p@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Magic SysRq extensions | expand |
On Mon, May 11, 2020 at 03:59:17PM +0200, Andrzej Pietrasiewicz wrote: > Some userland might want to implement a policy to signal a configured > process with a configured signal. This patch adds necessary kernel-side > infrastructure and the newly added handler is triggered with > Alt-Shift-SysRq-s. Optionally the userland can also specify the expected > name of parent process of the victim. THat's crazy, what "userspace" wants to do something like this that can't just do it by running a program? Why force the kernel to do it for them? And you don't document any of this :( greg k-h
Hi Andrzej,
I love your patch! Yet something to improve:
[auto build test ERROR on 2ef96a5bb12be62ef75b5828c0aab838ebb29cb8]
url: https://github.com/0day-ci/linux/commits/Andrzej-Pietrasiewicz/Magic-SysRq-extensions/20200514-151142
base: 2ef96a5bb12be62ef75b5828c0aab838ebb29cb8
config: alpha-defconfig (attached as .config)
compiler: alpha-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=alpha
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>
All errors (new ones prefixed by >>, old ones prefixed by <<):
drivers/tty/sysrq.c: In function 'sysrq_str_to_signal':
>> drivers/tty/sysrq.c:791:17: error: 'SIGSTKFLT' undeclared (first use in this function); did you mean 'SIGSTKSZ'?
791 | {"SIGSTKFLT", SIGSTKFLT},
| ^~~~~~~~~
| SIGSTKSZ
drivers/tty/sysrq.c:791:17: note: each undeclared identifier is reported only once for each function it appears in
vim +791 drivers/tty/sysrq.c
771
772 static void sysrq_str_to_signal(void)
773 {
774 static const struct signal_search signals[] = {
775 {"SIGHUP", SIGHUP},
776 {"SIGINT", SIGINT},
777 {"SIGQUIT", SIGQUIT},
778 {"SIGILL", SIGILL},
779 {"SIGTRAP", SIGTRAP},
780 {"SIGABRT", SIGABRT},
781 {"SIGIOT", SIGIOT},
782 {"SIGBUS", SIGBUS},
783 {"SIGFPE", SIGFPE},
784 {"SIGKILL", SIGKILL},
785 {"SIGUSR1", SIGUSR1},
786 {"SIGSEGV", SIGSEGV},
787 {"SIGUSR2", SIGUSR2},
788 {"SIGPIPE", SIGPIPE},
789 {"SIGALRM", SIGALRM},
790 {"SIGTERM", SIGTERM},
> 791 {"SIGSTKFLT", SIGSTKFLT},
792 {"SIGCHLD", SIGCHLD},
793 {"SIGCONT", SIGCONT},
794 {"SIGSTOP", SIGSTOP},
795 {"SIGTSTP", SIGTSTP},
796 {"SIGTTIN", SIGTTIN},
797 {"SIGTTOU", SIGTTOU},
798 {"SIGURG", SIGURG},
799 {"SIGXCPU", SIGXCPU},
800 {"SIGXFSZ", SIGXFSZ},
801 {"SIGVTALRM", SIGVTALRM},
802 {"SIGPROF", SIGPROF},
803 {"SIGWINCH", SIGWINCH},
804 {"SIGIO", SIGIO},
805 {"SIGPOLL", SIGPOLL},
806 {"SIGPWR", SIGPWR},
807 {"SIGSYS", SIGSYS},
808 };
809 int i;
810
811 if (!sysrq_signal)
812 return;
813
814 for (i = 0; i < ARRAY_SIZE(signals); ++i)
815 if (!strcmp(signals[i].name, sysrq_signal))
816 break;
817
818 if (i >= ARRAY_SIZE(signals)) {
819 pr_err("Unknown signal name %s", sysrq_signal);
820
821 return;
822 }
823
824 sysrq_signal_code = signals[i].code;
825 }
826
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index ab4121a446b4..a6e91e4ae304 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -437,6 +437,15 @@ static struct sysrq_key_op sysrq_unrt_op = { .enable_mask = SYSRQ_ENABLE_RTNICE, }; +static void sysrq_signal_configured(int key); + +static struct sysrq_key_op sysrq_signal_configured_op = { + .handler = sysrq_signal_configured, + .help_msg = "signal-configured-process(S)", + .action_msg = "Signal configured process", + .enable_mask = SYSRQ_ENABLE_SIGNAL, +}; + /* Key Operations table and lock */ static DEFINE_SPINLOCK(sysrq_key_table_lock); @@ -515,7 +524,7 @@ static struct sysrq_key_op *sysrq_key_table[62] = { NULL, /* P */ NULL, /* Q */ NULL, /* R */ - NULL, /* S */ + &sysrq_signal_configured_op, /* S */ NULL, /* T */ NULL, /* U */ NULL, /* V */ @@ -633,6 +642,10 @@ EXPORT_SYMBOL(handle_sysrq); #ifdef CONFIG_INPUT static int sysrq_reset_downtime_ms; static unsigned short sysrq_key = KEY_SYSRQ; +static char *sysrq_signalled; +static char *sysrq_signalled_parent; +static char *sysrq_signal; +static int sysrq_signal_code; /* Simple translation table for the SysRq keys */ static const unsigned char sysrq_xlate[KEY_CNT] = @@ -751,6 +764,106 @@ static void sysrq_detect_reset_sequence(struct sysrq_state *state, } } +struct signal_search { + const char *name; + int code; +}; + +static void sysrq_str_to_signal(void) +{ + static const struct signal_search signals[] = { + {"SIGHUP", SIGHUP}, + {"SIGINT", SIGINT}, + {"SIGQUIT", SIGQUIT}, + {"SIGILL", SIGILL}, + {"SIGTRAP", SIGTRAP}, + {"SIGABRT", SIGABRT}, + {"SIGIOT", SIGIOT}, + {"SIGBUS", SIGBUS}, + {"SIGFPE", SIGFPE}, + {"SIGKILL", SIGKILL}, + {"SIGUSR1", SIGUSR1}, + {"SIGSEGV", SIGSEGV}, + {"SIGUSR2", SIGUSR2}, + {"SIGPIPE", SIGPIPE}, + {"SIGALRM", SIGALRM}, + {"SIGTERM", SIGTERM}, + {"SIGSTKFLT", SIGSTKFLT}, + {"SIGCHLD", SIGCHLD}, + {"SIGCONT", SIGCONT}, + {"SIGSTOP", SIGSTOP}, + {"SIGTSTP", SIGTSTP}, + {"SIGTTIN", SIGTTIN}, + {"SIGTTOU", SIGTTOU}, + {"SIGURG", SIGURG}, + {"SIGXCPU", SIGXCPU}, + {"SIGXFSZ", SIGXFSZ}, + {"SIGVTALRM", SIGVTALRM}, + {"SIGPROF", SIGPROF}, + {"SIGWINCH", SIGWINCH}, + {"SIGIO", SIGIO}, + {"SIGPOLL", SIGPOLL}, + {"SIGPWR", SIGPWR}, + {"SIGSYS", SIGSYS}, + }; + int i; + + if (!sysrq_signal) + return; + + for (i = 0; i < ARRAY_SIZE(signals); ++i) + if (!strcmp(signals[i].name, sysrq_signal)) + break; + + if (i >= ARRAY_SIZE(signals)) { + pr_err("Unknown signal name %s", sysrq_signal); + + return; + } + + sysrq_signal_code = signals[i].code; +} + +static void sysrq_signal_configured(int key) +{ + struct task_struct *p; + + sysrq_str_to_signal(); + + if (!sysrq_signalled) { + pr_err("Unconfigured process name for %s", + sysrq_signal_configured_op.help_msg); + + return; + } + + if (!sysrq_signal_code) { + pr_err("Unconfigured signal for %s", + sysrq_signal_configured_op.help_msg); + + return; + } + + read_lock(&tasklist_lock); + for_each_process(p) { + if (p->flags & (PF_KTHREAD | PF_EXITING)) + continue; + if (is_global_init(p)) + continue; + if (strncmp(p->comm, sysrq_signalled, TASK_COMM_LEN)) + continue; + if (sysrq_signalled_parent + && strncmp(p->parent->comm, sysrq_signalled_parent, + TASK_COMM_LEN)) + continue; + + pr_err("%s: signal %d %s pid %u tgid %u\n", __func__, + sysrq_signal_code, sysrq_signalled, p->pid, p->tgid); + do_send_sig_info(sysrq_signal_code, SEND_SIG_PRIV, p, true); + } + read_unlock(&tasklist_lock); +} + static void sysrq_reinject_alt_sysrq(struct work_struct *work) { @@ -1048,8 +1161,16 @@ module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); module_param(sysrq_key, ushort, 0644); +module_param(sysrq_signalled, charp, 0644); +module_param(sysrq_signalled_parent, charp, 0644); +module_param(sysrq_signal, charp, 0644); + #else +static void sysrq_signal_configured(int key) +{ +} + static inline void sysrq_register_handler(void) { }
Some userland might want to implement a policy to signal a configured process with a configured signal. This patch adds necessary kernel-side infrastructure and the newly added handler is triggered with Alt-Shift-SysRq-s. Optionally the userland can also specify the expected name of parent process of the victim. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com> --- drivers/tty/sysrq.c | 123 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 122 insertions(+), 1 deletion(-)