From c1174876874dcf8986806e4dad3d7d07af20b439 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 31 May 2012 14:47:33 +0200 Subject: sched: Fix domain iteration Weird topologies can lead to asymmetric domain setups. This needs further consideration since these setups are typically non-minimal too. For now, make it work by adding an extra mask selecting which CPUs are allowed to iterate up. The topology that triggered it is the one from David Rientjes: 10 20 20 30 20 10 20 20 20 20 10 20 30 20 20 10 resulting in boxes that wouldn't even boot. Reported-by: David Rientjes Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-3p86l9cuaqnxz7uxsojmz5rm@git.kernel.org Signed-off-by: Ingo Molnar --- include/linux/sched.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index 6029d8c54476..ac321d753470 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -876,6 +876,8 @@ struct sched_group_power { * Number of busy cpus in this group. */ atomic_t nr_busy_cpus; + + unsigned long cpumask[0]; /* iteration mask */ }; struct sched_group { @@ -900,6 +902,15 @@ static inline struct cpumask *sched_group_cpus(struct sched_group *sg) return to_cpumask(sg->cpumask); } +/* + * cpumask masking which cpus in the group are allowed to iterate up the domain + * tree. + */ +static inline struct cpumask *sched_group_mask(struct sched_group *sg) +{ + return to_cpumask(sg->sgp->cpumask); +} + /** * group_first_cpu - Returns the first cpu in the cpumask of a sched_group. * @group: The group whose first cpu is to be returned. -- cgit v1.2.3 From bafb282df29c1524b1617019adebd6d0c3eb7a47 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Thu, 7 Jun 2012 14:21:11 -0700 Subject: c/r: prctl: update prctl_set_mm_exe_file() after mm->num_exe_file_vmas removal A fix for commit b32dfe377102 ("c/r: prctl: add ability to set new mm_struct::exe_file"). After removing mm->num_exe_file_vmas kernel keeps mm->exe_file until final mmput(), it never becomes NULL while task is alive. We can check for other mapped files in mm instead of checking mm->num_exe_file_vmas, and mark mm with flag MMF_EXE_FILE_CHANGED in order to forbid second changing of mm->exe_file. Signed-off-by: Konstantin Khlebnikov Reviewed-by: Cyrill Gorcunov Cc: Oleg Nesterov Cc: Matt Helsley Cc: Kees Cook Cc: KOSAKI Motohiro Cc: Tejun Heo Cc: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sched.h | 1 + kernel/sys.c | 31 +++++++++++++++++++------------ 2 files changed, 20 insertions(+), 12 deletions(-) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index 6029d8c54476..c688d4cc2e40 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -439,6 +439,7 @@ extern int get_dumpable(struct mm_struct *mm); /* leave room for more dump flags */ #define MMF_VM_MERGEABLE 16 /* KSM may merge identical pages */ #define MMF_VM_HUGEPAGE 17 /* set when VM_HUGEPAGE is set on vma */ +#define MMF_EXE_FILE_CHANGED 18 /* see prctl_set_mm_exe_file() */ #define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK) diff --git a/kernel/sys.c b/kernel/sys.c index 9ff89cb9657a..54f20fdee93c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1796,17 +1796,11 @@ static bool vma_flags_mismatch(struct vm_area_struct *vma, static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) { + struct vm_area_struct *vma; struct file *exe_file; struct dentry *dentry; int err; - /* - * Setting new mm::exe_file is only allowed when no VM_EXECUTABLE vma's - * remain. So perform a quick test first. - */ - if (mm->num_exe_file_vmas) - return -EBUSY; - exe_file = fget(fd); if (!exe_file) return -EBADF; @@ -1827,17 +1821,30 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) if (err) goto exit; + down_write(&mm->mmap_sem); + + /* + * Forbid mm->exe_file change if there are mapped other files. + */ + err = -EBUSY; + for (vma = mm->mmap; vma; vma = vma->vm_next) { + if (vma->vm_file && !path_equal(&vma->vm_file->f_path, + &exe_file->f_path)) + goto exit_unlock; + } + /* * The symlink can be changed only once, just to disallow arbitrary * transitions malicious software might bring in. This means one * could make a snapshot over all processes running and monitor * /proc/pid/exe changes to notice unusual activity if needed. */ - down_write(&mm->mmap_sem); - if (likely(!mm->exe_file)) - set_mm_exe_file(mm, exe_file); - else - err = -EBUSY; + err = -EPERM; + if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags)) + goto exit_unlock; + + set_mm_exe_file(mm, exe_file); +exit_unlock: up_write(&mm->mmap_sem); exit: -- cgit v1.2.3