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authorLinus Torvalds <torvalds@linux-foundation.org>2011-05-29 11:32:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-29 11:32:28 -0700
commit6345d24daf0c1fffe6642081d783cdf653ebaa5c (patch)
tree415a253621279111bd481d48cbb86174c70b952a /init
parentcab0d85c8dfcad4d799f9c294571440c6f1db091 (diff)
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mm: Fix boot crash in mm_alloc()
Thomas Gleixner reports that we now have a boot crash triggered by CONFIG_CPUMASK_OFFSTACK=y: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<c11ae035>] find_next_bit+0x55/0xb0 Call Trace: [<c11addda>] cpumask_any_but+0x2a/0x70 [<c102396b>] flush_tlb_mm+0x2b/0x80 [<c1022705>] pud_populate+0x35/0x50 [<c10227ba>] pgd_alloc+0x9a/0xf0 [<c103a3fc>] mm_init+0xec/0x120 [<c103a7a3>] mm_alloc+0x53/0xd0 which was introduced by commit de03c72cfce5 ("mm: convert mm->cpu_vm_cpumask into cpumask_var_t"), and is due to wrong ordering of mm_init() vs mm_init_cpumask Thomas wrote a patch to just fix the ordering of initialization, but I hate the new double allocation in the fork path, so I ended up instead doing some more radical surgery to clean it all up. Reported-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: Ingo Molnar <mingo@elte.hu> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init')
-rw-r--r--init/main.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/init/main.c b/init/main.c
index d2f1e086bf3..cafba67c13b 100644
--- a/init/main.c
+++ b/init/main.c
@@ -487,6 +487,7 @@ asmlinkage void __init start_kernel(void)
printk(KERN_NOTICE "%s", linux_banner);
setup_arch(&command_line);
mm_init_owner(&init_mm, &init_task);
+ mm_init_cpumask(&init_mm);
setup_command_line(command_line);
setup_nr_cpu_ids();
setup_per_cpu_areas();
@@ -510,7 +511,6 @@ asmlinkage void __init start_kernel(void)
sort_main_extable();
trap_init();
mm_init();
- BUG_ON(mm_init_cpumask(&init_mm, 0));
/*
* Set up the scheduler prior starting any interrupts (such as the