/* Demo leapsecond deadlock * by: John Stultz (john.stultz@linaro.org) * (C) Copyright IBM 2012 * (C) Copyright 2013, 2015 Linaro Limited * Licensed under the GPL * * This test demonstrates leapsecond deadlock that is possibe * on kernels from 2.6.26 to 3.3. * * WARNING: THIS WILL LIKELY HARDHANG SYSTEMS AND MAY LOSE DATA * RUN AT YOUR OWN RISK! * To build: * $ gcc leapcrash.c -o leapcrash -lrt */ #include #include #include #include #include #include #include #ifdef KTEST #include "../kselftest.h" #else static inline int ksft_exit_pass(void) { exit(0); } static inline int ksft_exit_fail(void) { exit(1); } #endif /* clear NTP time_status & time_state */ int clear_time_state(void) { struct timex tx; int ret; /* * We have to call adjtime twice here, as kernels * prior to 6b1859dba01c7 (included in 3.5 and * -stable), had an issue with the state machine * and wouldn't clear the STA_INS/DEL flag directly. */ tx.modes = ADJ_STATUS; tx.status = STA_PLL; ret = adjtimex(&tx); tx.modes = ADJ_STATUS; tx.status = 0; ret = adjtimex(&tx); return ret; } /* Make sure we cleanup on ctrl-c */ void handler(int unused) { clear_time_state(); exit(0); } int main(void) { struct timex tx; struct timespec ts; time_t next_leap; int count = 0; setbuf(stdout, NULL); signal(SIGINT, handler); signal(SIGKILL, handler); printf("This runs for a few minutes. Press ctrl-c to stop\n"); clear_time_state(); /* Get the current time */ clock_gettime(CLOCK_REALTIME, &ts); /* Calculate the next possible leap second 23:59:60 GMT */ next_leap = ts.tv_sec; next_leap += 86400 - (next_leap % 86400); for (count = 0; count < 20; count++) { struct timeval tv; /* set the time to 2 seconds before the leap */ tv.tv_sec = next_leap - 2; tv.tv_usec = 0; if (settimeofday(&tv, NULL)) { printf("Error: You're likely not running with proper (ie: root) permissions\n"); return ksft_exit_fail(); } tx.modes = 0; adjtimex(&tx); /* hammer on adjtime w/ STA_INS */ while (tx.time.tv_sec < next_leap + 1) { /* Set the leap second insert flag */ tx.modes = ADJ_STATUS; tx.status = STA_INS; adjtimex(&tx); } clear_time_state(); printf("."); } printf("[OK]\n"); return ksft_exit_pass(); } 1b63ecb1a349d50a6d69d1d6feb4a'/>
path: root/drivers/usb/gadget/function/f_ncm.c
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authorTejun Heo <tj@kernel.org>2017-01-26 16:47:28 -0500
committerTejun Heo <tj@kernel.org>2017-01-26 16:47:28 -0500
commit07cd12945551b63ecb1a349d50a6d69d1d6feb4a (patch)
tree75f65eba7eac9277971082a2d5a4cf1370562c0c /drivers/usb/gadget/function/f_ncm.c
parent7ce7d89f48834cefece7804d38fc5d85382edf77 (diff)
cgroup: don't online subsystems before cgroup_name/path() are operational
While refactoring cgroup creation, a5bca2152036 ("cgroup: factor out cgroup_create() out of cgroup_mkdir()") incorrectly onlined subsystems before the new cgroup is associated with it kernfs_node. This is fine for cgroup proper but cgroup_name/path() depend on the associated kernfs_node and if a subsystem makes the new cgroup_subsys_state visible, which they're allowed to after onlining, it can lead to NULL dereference. The current code performs cgroup creation and subsystem onlining in cgroup_create() and cgroup_mkdir() makes the cgroup and subsystems visible afterwards. There's no reason to online the subsystems early and we can simply drop cgroup_apply_control_enable() call from cgroup_create() so that the subsystems are onlined and made visible at the same time. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Fixes: a5bca2152036 ("cgroup: factor out cgroup_create() out of cgroup_mkdir()") Cc: stable@vger.kernel.org # v4.6+
Diffstat (limited to 'drivers/usb/gadget/function/f_ncm.c')