From 18c6ac383f3e46cfce08d0bf972705852a4e1268 Mon Sep 17 00:00:00 2001 From: Sunil Mushran Date: Mon, 7 Jul 2008 10:06:29 -0700 Subject: [PATCH] ocfs2/dlm: Fixes oops in dlm_new_lockres() Patch fixes a race that can result in an oops while adding a lockres to the dlm lockres tracking list. Bug introduced by mainline commit 29576f8bb54045be944ba809d4fca1ad77c94165. Signed-off-by: Sunil Mushran Signed-off-by: Mark Fasheh --- fs/ocfs2/dlm/dlmmaster.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs') diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index efc015c6128a..44f87caf3683 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -606,7 +606,9 @@ static void dlm_init_lockres(struct dlm_ctxt *dlm, res->last_used = 0; + spin_lock(&dlm->spinlock); list_add_tail(&res->tracking, &dlm->tracking_list); + spin_unlock(&dlm->spinlock); memset(res->lvb, 0, DLM_LVB_LEN); memset(res->refmap, 0, sizeof(res->refmap)); -- cgit v1.2.3 From e988cf1cfed4ed80bf40528e655fe18bed6a38b6 Mon Sep 17 00:00:00 2001 From: Mark Fasheh Date: Thu, 10 Jul 2008 09:25:39 -0700 Subject: ocfs2: Fix flags in ocfs2_file_lock The stack-glue merge changed the way we use flags in dlmglue in that we now use the fs/dlm equivalents. Unfortunately, a merge error left the new flock code only partially updated. This took a while to show up though, because the lock level constants are actually identical between o2dlm and fs/dlm. The *_CONVERT and *_NOQUEUE flags have different values though, which is eventually causing a crash in flags_to_o2dlm(). Signed-off-by: Mark Fasheh --- fs/ocfs2/dlmglue.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'fs') diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c index 394d25a131a5..80e20d9f2780 100644 --- a/fs/ocfs2/dlmglue.c +++ b/fs/ocfs2/dlmglue.c @@ -1554,8 +1554,8 @@ out: */ int ocfs2_file_lock(struct file *file, int ex, int trylock) { - int ret, level = ex ? LKM_EXMODE : LKM_PRMODE; - unsigned int lkm_flags = trylock ? LKM_NOQUEUE : 0; + int ret, level = ex ? DLM_LOCK_EX : DLM_LOCK_PR; + unsigned int lkm_flags = trylock ? DLM_LKF_NOQUEUE : 0; unsigned long flags; struct ocfs2_file_private *fp = file->private_data; struct ocfs2_lock_res *lockres = &fp->fp_flock; @@ -1582,7 +1582,7 @@ int ocfs2_file_lock(struct file *file, int ex, int trylock) * Get the lock at NLMODE to start - that way we * can cancel the upconvert request if need be. */ - ret = ocfs2_lock_create(osb, lockres, LKM_NLMODE, 0); + ret = ocfs2_lock_create(osb, lockres, DLM_LOCK_NL, 0); if (ret < 0) { mlog_errno(ret); goto out; @@ -1597,7 +1597,7 @@ int ocfs2_file_lock(struct file *file, int ex, int trylock) } lockres->l_action = OCFS2_AST_CONVERT; - lkm_flags |= LKM_CONVERT; + lkm_flags |= DLM_LKF_CONVERT; lockres->l_requested = level; lockres_or_flags(lockres, OCFS2_LOCK_BUSY); @@ -1664,7 +1664,7 @@ void ocfs2_file_unlock(struct file *file) if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) return; - if (lockres->l_level == LKM_NLMODE) + if (lockres->l_level == DLM_LOCK_NL) return; mlog(0, "Unlock: \"%s\" flags: 0x%lx, level: %d, act: %d\n", @@ -1678,11 +1678,11 @@ void ocfs2_file_unlock(struct file *file) lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED); lockres->l_blocking = DLM_LOCK_EX; - gen = ocfs2_prepare_downconvert(lockres, LKM_NLMODE); + gen = ocfs2_prepare_downconvert(lockres, DLM_LOCK_NL); lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0); spin_unlock_irqrestore(&lockres->l_lock, flags); - ret = ocfs2_downconvert_lock(osb, lockres, LKM_NLMODE, 0, gen); + ret = ocfs2_downconvert_lock(osb, lockres, DLM_LOCK_NL, 0, gen); if (ret) { mlog_errno(ret); return; -- cgit v1.2.3 From 96a8e13ed44e380fc2bb6c711d74d5ba698c00b2 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 10 Jul 2008 21:19:20 +0100 Subject: exec: fix stack excutability without PT_GNU_STACK Kernel Bugzilla #11063 points out that on some architectures (e.g. x86_32) exec'ing an ELF without a PT_GNU_STACK program header should default to an executable stack; but this got broken by the unlimited argv feature because stack vma is now created before the right personality has been established: so breaking old binaries using nested function trampolines. Therefore re-evaluate VM_STACK_FLAGS in setup_arg_pages, where stack vm_flags used to be set, before the mprotect_fixup. Checking through our existing VM_flags, none would have changed since insert_vm_struct: so this seems safer than finding a way through the personality labyrinth. Reported-by: pageexec@freemail.hu Signed-off-by: Hugh Dickins Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- fs/exec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/exec.c b/fs/exec.c index da94a6f05df3..fd9234379e8d 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -610,7 +610,7 @@ int setup_arg_pages(struct linux_binprm *bprm, bprm->exec -= stack_shift; down_write(&mm->mmap_sem); - vm_flags = vma->vm_flags; + vm_flags = VM_STACK_FLAGS; /* * Adjust stack execute permissions; explicitly enable for -- cgit v1.2.3 From 49641f1acfdfd437ed9b0a70b86bf36626c02afe Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 11 Jul 2008 17:43:55 +1000 Subject: Fix reference counting race on log buffers When we release the iclog, we do an atomic_dec_and_lock to determine if we are the last reference and need to trigger update of log headers and writeout. However, in xlog_state_get_iclog_space() we also need to check if we have the last reference count there. If we do, we release the log buffer, otherwise we decrement the reference count. But the compare and decrement in xlog_state_get_iclog_space() is not atomic, so both places can see a reference count of 2 and neither will release the iclog. That leads to a filesystem hang. Close the race by replacing the atomic_read() and atomic_dec() pair with atomic_add_unless() to ensure that they are executed atomically. Signed-off-by: Dave Chinner Reviewed-by: Tim Shimmin Tested-by: Eric Sandeen Signed-off-by: Linus Torvalds --- fs/xfs/xfs_log.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index afaee301b0ee..ad3d26ddfe31 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -2427,13 +2427,20 @@ restart: if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) { xlog_state_switch_iclogs(log, iclog, iclog->ic_size); - /* If I'm the only one writing to this iclog, sync it to disk */ - if (atomic_read(&iclog->ic_refcnt) == 1) { + /* + * If I'm the only one writing to this iclog, sync it to disk. + * We need to do an atomic compare and decrement here to avoid + * racing with concurrent atomic_dec_and_lock() calls in + * xlog_state_release_iclog() when there is more than one + * reference to the iclog. + */ + if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) { + /* we are the only one */ spin_unlock(&log->l_icloglock); - if ((error = xlog_state_release_iclog(log, iclog))) + error = xlog_state_release_iclog(log, iclog); + if (error) return error; } else { - atomic_dec(&iclog->ic_refcnt); spin_unlock(&log->l_icloglock); } goto restart; -- cgit v1.2.3