From 1fb9341ac34825aa40354e74d9a2c69df7d2c304 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Sat, 12 Jan 2013 13:27:34 +1030 Subject: module: put modules in list much earlier. Prarit's excellent bug report: > In recent Fedora releases (F17 & F18) some users have reported seeing > messages similar to > > [ 15.478160] kvm: Could not allocate 304 bytes percpu data > [ 15.478174] PERCPU: allocation failed, size=304 align=32, alloc from > reserved chunk failed > > during system boot. In some cases, users have also reported seeing this > message along with a failed load of other modules. > > What is happening is systemd is loading an instance of the kvm module for > each cpu found (see commit e9bda3b). When the module load occurs the kernel > currently allocates the modules percpu data area prior to checking to see > if the module is already loaded or is in the process of being loaded. If > the module is already loaded, or finishes load, the module loading code > releases the current instance's module's percpu data. Now we have a new state MODULE_STATE_UNFORMED, we can insert the module into the list (and thus guarantee its uniqueness) before we allocate the per-cpu region. Reported-by: Prarit Bhargava Signed-off-by: Rusty Russell Tested-by: Prarit Bhargava --- lib/bug.c | 1 + 1 file changed, 1 insertion(+) (limited to 'lib/bug.c') diff --git a/lib/bug.c b/lib/bug.c index a28c1415357c..d0cdf14c651a 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -55,6 +55,7 @@ static inline unsigned long bug_addr(const struct bug_entry *bug) } #ifdef CONFIG_MODULES +/* Updates are protected by module mutex */ static LIST_HEAD(module_bug_list); static const struct bug_entry *module_find_bug(unsigned long bugaddr) -- cgit v1.2.2 From 373d4d099761cb1f637bed488ab3871945882273 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 21 Jan 2013 17:17:39 +1030 Subject: taint: add explicit flag to show whether lock dep is still OK. Fix up all callers as they were before, with make one change: an unsigned module taints the kernel, but doesn't turn off lockdep. Signed-off-by: Rusty Russell --- lib/bug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'lib/bug.c') diff --git a/lib/bug.c b/lib/bug.c index d0cdf14c651a..168603477f02 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -166,7 +166,8 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) print_modules(); show_regs(regs); print_oops_end_marker(); - add_taint(BUG_GET_TAINT(bug)); + /* Just a warning, don't kill lockdep. */ + add_taint(BUG_GET_TAINT(bug), LOCKDEP_STILL_OK); return BUG_TRAP_TYPE_WARN; } -- cgit v1.2.2