2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Tony Battersby commit a68e61e8ff2d46327a37b69056998b47745db6fa upstream. shm_get_stat() assumes that the inode is a "struct shmem_inode_info", which is incorrect for !CONFIG_SHMEM (see fs/ramfs/inode.c: ramfs_get_inode() vs. mm/shmem.c: shmem_get_inode()). This bad assumption can cause shmctl(SHM_INFO) to lockup when shm_get_stat() tries to spin_lock(&info->lock). Users of !CONFIG_SHMEM may encounter this lockup simply by invoking the 'ipcs' command. Reported by Jiri Olsa back in February 2008: http://lkml.org/lkml/2008/2/29/74 Signed-off-by: Tony Battersby Cc: Jiri Kosina Reported-by: Jiri Olsa Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- ipc/shm.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/ipc/shm.c +++ b/ipc/shm.c @@ -565,11 +565,15 @@ static void shm_get_stat(struct ipc_name struct hstate *h = hstate_file(shp->shm_file); *rss += pages_per_huge_page(h) * mapping->nrpages; } else { +#ifdef CONFIG_SHMEM struct shmem_inode_info *info = SHMEM_I(inode); spin_lock(&info->lock); *rss += inode->i_mapping->nrpages; *swp += info->swapped; spin_unlock(&info->lock); +#else + *rss += inode->i_mapping->nrpages; +#endif } total++; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/