* Yu Zhao <yuzhao@xxxxxxxxxx> [220419 19:23]: > On Tue, Apr 19, 2022 at 5:18 PM Liam Howlett <liam.howlett@xxxxxxxxxx> wrote: > > > > * Yu Zhao <yuzhao@xxxxxxxxxx> [220419 17:59]: > > > On Tue, Apr 19, 2022 at 9:51 AM Liam Howlett <liam.howlett@xxxxxxxxxx> wrote: > > > > > > > > * Yu Zhao <yuzhao@xxxxxxxxxx> [220416 15:30]: > > > > > On Sat, Apr 16, 2022 at 9:19 AM Liam Howlett <liam.howlett@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > <snipped> > > > > > > > > > > > How did you hit this issue? Just on boot? > > > > > > > > > > I was hoping this is known to you or you have something I can verify for you. > > > > > > > > > > > > Thanks, yes. I believe that both crashes are the same root cause. The > > > > cause is that I was not cleaning up after the kmem bulk allocation > > > > failure on my side. Please test with this patch. > > > > > > Thanks. I applied this patch and hit a LOCKDEP and then a BUG_ON: > > > > > > lib/maple_tree.c:847 suspicious rcu_dereference_protected() usage! > > > Call Trace: > > > <TASK> > > > dump_stack_lvl+0x6c/0x9a > > > dump_stack+0x10/0x12 > > > lockdep_rcu_suspicious+0x12c/0x140 > > > __mt_destroy+0x96/0xd0 > > > exit_mmap+0x2a0/0x360 > > > __mmput+0x34/0x100 > > > mmput+0x2f/0x40 > > > free_bprm+0x64/0xe0 > > > kernel_execve+0x129/0x330 > > > call_usermodehelper_exec_async+0xd8/0x130 > > > ? proc_cap_handler+0x210/0x210 > > > ret_from_fork+0x1f/0x30 > > > </TASK> > > > > Thanks - I'm not sure how this got through, but this should fix it. > > > > This should be added to 4236a642ad185 to avoid the LOCKDEP issue. > > > > --- a/mm/mmap.c > > +++ b/mm/mmap.c > > @@ -3163,9 +3163,9 @@ void exit_mmap(struct mm_struct *mm) > > > > BUG_ON(count != mm->map_count); > > > > - mmap_write_unlock(mm); > > trace_exit_mmap(mm); > > __mt_destroy(&mm->mm_mt); > > + mmap_write_unlock(mm); > > vm_unacct_memory(nr_accounted); > > } > > Will try this. Andrew, Please add this fix to the commit 4236a642ad185 "mm: start tracking VMAs with maple tree" I've attached the patch for your convenience. Thanks, Liam
From ee4b1fc24f30cff25257b2a77b6f44aad1db6e19 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> Date: Wed, 20 Apr 2022 09:37:50 -0400 Subject: [PATCH] mm: Fix commit "mm: start tracking VMAs with maple tree" Hold the lock for the destruction of the maple tree to avoid lockdep issues - and potentially process_mrelease. Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> --- mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index f172f3aba90f..dbfd3576b6d0 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3163,9 +3163,9 @@ void exit_mmap(struct mm_struct *mm) BUG_ON(count != mm->map_count); - mmap_write_unlock(mm); trace_exit_mmap(mm); __mt_destroy(&mm->mm_mt); + mmap_write_unlock(mm); vm_unacct_memory(nr_accounted); } -- 2.34.1
