From 2c10636a0b9c689450e85f9945583920f50337c9 Mon Sep 17 00:00:00 2001 From: Nathan Fontenot Date: Thu, 15 Feb 2018 21:27:41 -0600 Subject: [PATCH] powerpc/pseries: Check for zero filled ibm,dynamic-memory property Some versions of QEMU will produce an ibm,dynamic-reconfiguration-memory node with a ibm,dynamic-memory property that is zero-filled. This causes the drmem code to oops trying to parse this property. The fix for this is to validate that the property does contain LMB entries before trying to parse it and bail if the count is zero. Oops: Kernel access of bad area, sig: 11 [#1] DAR: 0000000000000010 NIP read_drconf_v1_cell+0x54/0x9c LR read_drconf_v1_cell+0x48/0x9c Call Trace: __param_initcall_debug+0x0/0x28 (unreliable) drmem_init+0x144/0x2f8 do_one_initcall+0x64/0x1d0 kernel_init_freeable+0x298/0x38c kernel_init+0x24/0x160 ret_from_kernel_thread+0x5c/0xb4 The ibm,dynamic-reconfiguration-memory device tree property generated that causes this: ibm,dynamic-reconfiguration-memory { ibm,lmb-size = <0x0 0x10000000>; ibm,memory-flags-mask = <0xff>; ibm,dynamic-memory = <0x0 0x0 0x0 0x0 0x0 0x0>; linux,phandle = <0x7e57eed8>; ibm,associativity-lookup-arrays = <0x1 0x4 0x0 0x0 0x0 0x0>; ibm,memory-preservation-time = <0x0>; }; Signed-off-by: Nathan Fontenot Reviewed-by: Cyril Bur Tested-by: Daniel Black [mpe: Trim oops report] Signed-off-by: Michael Ellerman --- arch/powerpc/mm/drmem.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/powerpc/mm/drmem.c b/arch/powerpc/mm/drmem.c index 1604110..916844f 100644 --- a/arch/powerpc/mm/drmem.c +++ b/arch/powerpc/mm/drmem.c @@ -216,6 +216,8 @@ static void __init __walk_drmem_v1_lmbs(const __be32 *prop, const __be32 *usm, u32 i, n_lmbs; n_lmbs = of_read_number(prop++, 1); + if (n_lmbs == 0) + return; for (i = 0; i < n_lmbs; i++) { read_drconf_v1_cell(&lmb, &prop); @@ -245,6 +247,8 @@ static void __init __walk_drmem_v2_lmbs(const __be32 *prop, const __be32 *usm, u32 i, j, lmb_sets; lmb_sets = of_read_number(prop++, 1); + if (lmb_sets == 0) + return; for (i = 0; i < lmb_sets; i++) { read_drconf_v2_cell(&dr_cell, &prop); @@ -354,6 +358,8 @@ static void __init init_drmem_v1_lmbs(const __be32 *prop) struct drmem_lmb *lmb; drmem_info->n_lmbs = of_read_number(prop++, 1); + if (drmem_info->n_lmbs == 0) + return; drmem_info->lmbs = kcalloc(drmem_info->n_lmbs, sizeof(*lmb), GFP_KERNEL); @@ -373,6 +379,8 @@ static void __init init_drmem_v2_lmbs(const __be32 *prop) int lmb_index; lmb_sets = of_read_number(prop++, 1); + if (lmb_sets == 0) + return; /* first pass, calculate the number of LMBs */ p = prop; -- 2.7.4