Commit-ID: 40814f6805a524130a5ec313871147f7aa9b5318 Gitweb: http://git.kernel.org/tip/40814f6805a524130a5ec313871147f7aa9b5318 Author: Oleg Nesterov <o...@redhat.com> AuthorDate: Mon, 19 May 2014 20:41:36 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 5 Jun 2014 12:30:11 +0200
uprobes: Teach copy_insn() to support tmpfs tmpfs is widely used but as Denys reports shmem_aops doesn't have ->readpage() and thus you can't probe a binary on this filesystem. As Hugh suggested we can use shmem_read_mapping_page() in this case, just we need to check shmem_mapping() if ->readpage == NULL. Reported-by: Denys Vlasenko <dvlas...@redhat.com> Suggested-by: Hugh Dickins <hu...@google.com> Signed-off-by: Oleg Nesterov <o...@redhat.com> Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Cc: Arnaldo Carvalho de Melo <a...@kernel.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Link: http://lkml.kernel.org/r/20140519184136.gb6...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/events/uprobes.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index c56b13e..6bfb671 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -36,6 +36,7 @@ #include "../../mm/internal.h" /* munlock_vma_page */ #include <linux/percpu-rwsem.h> #include <linux/task_work.h> +#include <linux/shmem_fs.h> #include <linux/uprobes.h> @@ -537,10 +538,14 @@ static int __copy_insn(struct address_space *mapping, struct file *filp, { struct page *page; /* - * Ensure that the page that has the original instruction is - * populated and in page-cache. + * Ensure that the page that has the original instruction is populated + * and in page-cache. If ->readpage == NULL it must be shmem_mapping(), + * see uprobe_register(). */ - page = read_mapping_page(mapping, offset >> PAGE_CACHE_SHIFT, filp); + if (mapping->a_ops->readpage) + page = read_mapping_page(mapping, offset >> PAGE_CACHE_SHIFT, filp); + else + page = shmem_read_mapping_page(mapping, offset >> PAGE_CACHE_SHIFT); if (IS_ERR(page)) return PTR_ERR(page); @@ -876,8 +881,8 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * if (!uc->handler && !uc->ret_handler) return -EINVAL; - /* copy_insn()->read_mapping_page() needs ->readpage() */ - if (!inode->i_mapping->a_ops->readpage) + /* copy_insn() uses read_mapping_page() or shmem_read_mapping_page() */ + if (!inode->i_mapping->a_ops->readpage && !shmem_mapping(inode->i_mapping)) return -EIO; /* Racy, just to catch the obvious mistakes */ if (offset > i_size_read(inode)) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
