#define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #define NSIO 0xb7 #define NS_GET_USERNS _IO(NSIO, 0x1) #define pr_err(fmt, ...) \ ({ \ fprintf(stderr, "%s:%d:" fmt ": %m\n", \ __func__, __LINE__, ##__VA_ARGS__); \ 1; \ }) int main(int argc, char *argvp[]) { int pfd[2], ns, uns, init_uns; struct stat st1, st2; char path[128]; pid_t pid; char c; if (pipe(pfd)) return 1; pid = fork(); if (pid < 0) return pr_err("fork"); if (pid == 0) { prctl(PR_SET_PDEATHSIG, SIGKILL); if (unshare(CLONE_NEWUTS | CLONE_NEWUSER)) return pr_err("unshare"); close(pfd[0]); close(pfd[1]); while (1) sleep(1); return 0; } close(pfd[1]); if (read(pfd[0], &c, 1) != 0) return pr_err("Unable to read from pipe"); close(pfd[0]); snprintf(path, sizeof(path), "/proc/%d/ns/uts", pid); ns = open(path, O_RDONLY); if (ns < 0) return pr_err("Unable to open %s", path); uns = ioctl(ns, NS_GET_USERNS); if (uns < 0) return pr_err("Unable to get an owning user namespace"); if (fstat(uns, &st1)) return pr_err("fstat"); snprintf(path, sizeof(path), "/proc/%d/ns/user", pid); if (stat(path, &st2)) return pr_err("stat"); if (st1.st_ino != st2.st_ino) return pr_err("NS_GET_USERNS returned a wrong namespace"); init_uns = ioctl(uns, NS_GET_USERNS); if (uns < 0) return pr_err("Unable to get an owning user namespace"); if (ioctl(init_uns, NS_GET_USERNS) >= 0 || errno != EPERM) return pr_err("Don't get EPERM"); if (unshare(CLONE_NEWUSER)) return pr_err("unshare"); if (ioctl(ns, NS_GET_USERNS) >= 0 || errno != EPERM) return pr_err("Don't get EPERM"); if (ioctl(init_uns, NS_GET_USERNS) >= 0 || errno != EPERM) return pr_err("Don't get EPERM"); kill(pid, SIGKILL); wait(NULL); return 0; } 6cae7'>treecommitdiff
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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-30 19:27:10 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-31 09:13:49 -0500
commit79c6f448c8b79c321e4a1f31f98194e4f6b6cae7 (patch)
tree370efda701f03cccf21e02bb1fdd3b852547d75c /sound/isa/gus/gusextreme.c
parent0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff)
tracing: Fix hwlat kthread migration
The hwlat tracer creates a kernel thread at start of the tracer. It is pinned to a single CPU and will move to the next CPU after each period of running. If the user modifies the migration thread's affinity, it will not change after that happens. The original code created the thread at the first instance it was called, but later was changed to destroy the thread after the tracer was finished, and would not be created until the next instance of the tracer was established. The code that initialized the affinity was only called on the initial instantiation of the tracer. After that, it was not initialized, and the previous affinity did not match the current newly created one, making it appear that the user modified the thread's affinity when it did not, and the thread failed to migrate again. Cc: stable@vger.kernel.org Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'sound/isa/gus/gusextreme.c')