(+Will, Catalin) On Fri, Oct 20, 2017 at 1:27 PM, tip-bot for Kirill A. Shutemov <tip...@zytor.com> wrote: > Commit-ID: 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4 > Gitweb: > https://git.kernel.org/tip/83e3c48729d9ebb7af5a31a504f3fd6aff0348c4 > Author: Kirill A. Shutemov <kirill.shute...@linux.intel.com> > AuthorDate: Fri, 29 Sep 2017 17:08:16 +0300 > Committer: Ingo Molnar <mi...@kernel.org> > CommitDate: Fri, 20 Oct 2017 13:07:09 +0200 > > mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y > > Size of the mem_section[] array depends on the size of the physical address > space. > > In preparation for boot-time switching between paging modes on x86-64 > we need to make the allocation of mem_section[] dynamic, because otherwise > we waste a lot of RAM: with CONFIG_NODE_SHIFT=10, mem_section[] size is 32kB > for 4-level paging and 2MB for 5-level paging mode. > > The patch allocates the array on the first call to > sparse_memory_present_with_active_regions(). >
I am seeing a boot failure with this patch in linux-next today(20171102) Unable to handle kernel NULL pointer dereference at virtual address 00000000 Mem abort info: ESR = 0x96000004 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 [0000000000000000] user address but active_mm is swapper Internal error: Oops: 96000004 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 4.14.0-rc7-next-20171102 #133 Hardware name: ARM Juno development board (r2) (DT) task: ffff000008f82a80 task.stack: ffff000008f70000 pstate: 200000c5 (nzCv daIF -PAN -UAO) pc : memory_present+0x5c/0xe8 lr : memory_present+0x34/0xe8 sp : ffff000008f73e90 x29: ffff000008f73e90 x28: 0000000080e60018 x27: 00000000fd9b8d18 x26: 0000000000000105 x25: 0000000000000000 x24: ffff0000090c4000 x23: 0000000000000000 x22: ffff0000090c4000 x21: 0000000000080000 x20: 0000000000000004 x19: 0000000000000000 x18: 0000000000000010 x17: 0000000000000001 x16: 0000000000000000 x15: ffffffffffffffff x14: ffff00008909a3af x13: ffff00000909a3bd x12: ffff000008f79df0 x11: ffff000008590de8 x10: ffff000008f9c7f0 x9 : 0000000000000000 x8 : ffff80097ffccc80 x7 : 0000000000000000 x6 : 000000000000003f x5 : ffff000008f79fc0 x4 : 0000000000000001 x3 : 0000001000000000 x2 : 00000000000e0000 x1 : 0000000000080000 x0 : 0000000000000000 Process swapper (pid: 0, stack limit = 0xffff000008f70000) Call trace: memory_present+0x5c/0xe8 bootmem_init+0x90/0x114 setup_arch+0x190/0x4a0 start_kernel+0x64/0x3a8 Code: 54000449 d35afeb3 f94032c0 d37df273 (f8736800) random: get_random_bytes called from print_oops_end_marker+0x4c/0x68 with crng_init=0 ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Attempted to kill the idle task! ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
