From f1af98c7629a1b76fd7336decbc776acdeed2120 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Mon, 4 Oct 2010 14:57:39 -0700 Subject: memblock: Fix wraparound in find_region() When trying to find huge range for crashkernel, get [ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: at arch/x86/mm/memblock.c:248 memblock_x86_reserve_range+0x40/0x7a() [ 0.000000] Hardware name: Sun Fire x4800 [ 0.000000] memblock_x86_reserve_range: wrong range [0xffffffff37000000, 0x137000000) [ 0.000000] Modules linked in: [ 0.000000] Pid: 0, comm: swapper Not tainted 2.6.36-rc5-tip-yh-01876-g1cac214-dirty #59 [ 0.000000] Call Trace: [ 0.000000] [] ? memblock_x86_reserve_range+0x40/0x7a [ 0.000000] [] warn_slowpath_common+0x85/0x9e [ 0.000000] [] warn_slowpath_fmt+0x6e/0x70 [ 0.000000] [] ? memblock_find_region+0x40/0x78 [ 0.000000] [] ? memblock_find_base+0x9a/0xb9 [ 0.000000] [] memblock_x86_reserve_range+0x40/0x7a [ 0.000000] [] setup_arch+0x99d/0xb2a [ 0.000000] [] ? trace_hardirqs_off+0xd/0xf [ 0.000000] [] ? _raw_spin_unlock_irqrestore+0x3d/0x4c [ 0.000000] [] start_kernel+0xde/0x3f1 [ 0.000000] [] x86_64_start_reservations+0xa0/0xa4 [ 0.000000] [] x86_64_start_kernel+0x106/0x10d [ 0.000000] ---[ end trace a7919e7f17c0a725 ]--- [ 0.000000] Reserving 8192MB of memory at 17592186041200MB for crashkernel (System RAM: 526336MB) This is caused by a wraparound in the test due to size > end; explicitly check for this condition and fail. Signed-off-by: Yinghai Lu LKML-Reference: <4CAA4DD3.1080401@kernel.org> Signed-off-by: H. Peter Anvin --- mm/memblock.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/memblock.c b/mm/memblock.c index d5d63ac1fd83..9ad39690a2bd 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -105,13 +105,18 @@ static phys_addr_t __init memblock_find_region(phys_addr_t start, phys_addr_t en phys_addr_t base, res_base; long j; + /* In case, huge size is requested */ + if (end < size) + return MEMBLOCK_ERROR; + + base = memblock_align_down((end - size), align); + /* Prevent allocations returning 0 as it's also used to * indicate an allocation failure */ if (start == 0) start = PAGE_SIZE; - base = memblock_align_down((end - size), align); while (start <= base) { j = memblock_overlaps_region(&memblock.reserved, base, size); if (j < 0) -- cgit v1.2.3