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 de03c72c ("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>
parent
cab0d85c
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