Re: [PATCH v3 04/25] kcsan: Add core support for a subset of weak memory modeling
From: "Paul E. McKenney" <paulmck@kernel.org>
Date: 2021-12-03 21:09:00
Also in:
linux-arch, linux-kbuild, linux-mm, lkml, llvm
On Fri, Dec 03, 2021 at 08:50:20AM -0800, Paul E. McKenney wrote:
On Fri, Dec 03, 2021 at 09:56:45AM +0100, Marco Elver wrote:quoted
On Tue, Nov 30, 2021 at 12:44PM +0100, Marco Elver wrote: [...]quoted
v3: * Remove kcsan_noinstr hackery, since we now try to avoid adding any instrumentation to .noinstr.text in the first place.[...] I missed some cleanups after changes from v2 to v3 -- the below cleanup is missing. Full replacement patch attached.I pulled this into -rcu with the other patches from your v3 post, thank you all!
A few quick tests located the following: [ 0.635383] INFO: trying to register non-static key. [ 0.635804] The code is fine but needs lockdep annotation, or maybe [ 0.636194] you didn't initialize this object before use? [ 0.636194] turning off the locking correctness validator. [ 0.636194] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0-rc1+ #3208 [ 0.636194] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 [ 0.636194] Call Trace: [ 0.636194] <TASK> [ 0.636194] dump_stack_lvl+0x88/0xd8 [ 0.636194] dump_stack+0x15/0x1b [ 0.636194] register_lock_class+0x6b3/0x840 [ 0.636194] ? __this_cpu_preempt_check+0x1d/0x30 [ 0.636194] __lock_acquire+0x81/0xee0 [ 0.636194] ? lock_is_held_type+0xf1/0x160 [ 0.636194] lock_acquire+0xce/0x230 [ 0.636194] ? test_barrier+0x490/0x14c7 [ 0.636194] ? lock_is_held_type+0xf1/0x160 [ 0.636194] ? test_barrier+0x490/0x14c7 [ 0.636194] _raw_spin_lock+0x36/0x50 [ 0.636194] ? test_barrier+0x490/0x14c7 [ 0.636194] ? kcsan_init+0xf/0x80 [ 0.636194] test_barrier+0x490/0x14c7 [ 0.636194] ? kcsan_debugfs_init+0x1f/0x1f [ 0.636194] kcsan_selftest+0x47/0xa0 [ 0.636194] do_one_initcall+0x104/0x230 [ 0.636194] ? rcu_read_lock_sched_held+0x5b/0xc0 [ 0.636194] ? kernel_init+0x1c/0x200 [ 0.636194] do_initcall_level+0xa5/0xb6 [ 0.636194] do_initcalls+0x66/0x95 [ 0.636194] do_basic_setup+0x1d/0x23 [ 0.636194] kernel_init_freeable+0x254/0x2ed [ 0.636194] ? rest_init+0x290/0x290 [ 0.636194] kernel_init+0x1c/0x200 [ 0.636194] ? rest_init+0x290/0x290 [ 0.636194] ret_from_fork+0x22/0x30 [ 0.636194] </TASK> When running without the new patch series, this splat does not appear. Do I need a toolchain upgrade? I see the Clang 14.0 in the cover letter, but that seems to apply only to non-x86 architectures. $ clang-11 -v Ubuntu clang version 11.1.0-++20210805102428+1fdec59bffc1-1~exp1~20210805203044.169 Thanx, Paul