Commit-ID: c6ee7a548e2c291398b4f32c1f741c66b9f98e1c
Gitweb: https://git.kernel.org/tip/c6ee7a548e2c291398b4f32c1f741c66b9f98e1c
Author: Dave Jiang <dave.ji...@intel.com>
AuthorDate: Thu, 25 Oct 2018 13:26:45 -0700
Committer: Thomas Gleixner <t...@linutronix.de>
CommitDate: Tue, 30 Oct 2018 11:36:43 +0100
x86/numa_emulation: Fix uniform-split numa emulation
The numa_emulation() routine in the 'uniform' case walks through all the
physical 'memblk' instances and divides them into N emulated nodes with
split_nodes_size_interleave_uniform(). As each physical node is consumed it
is removed from the physical memblk array in the numa_remove_memblk_from()
helper.
Since split_nodes_size_interleave_uniform() handles advancing the array as
the 'memblk' is consumed it is expected that the base of the array is
always specified as the argument.
Otherwise, on multi-socket (> 2) configurations the uniform-split
capability can generate an invalid numa configuration leading to boot
failures with signatures like the following:
rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
Sending NMI from CPU 0 to CPUs 2:
NMI backtrace for cpu 2
CPU: 2 PID: 1332 Comm: pgdatinit0 Not tainted
4.19.0-rc8-next-20181019-baseline #59
RIP: 0010:__init_single_page.isra.74+0x81/0x90
[..]
Call Trace:
deferred_init_pages+0xaa/0xe3
deferred_init_memmap+0x18f/0x318
kthread+0xf8/0x130
? deferred_free_pages.isra.105+0xc9/0xc9
? kthread_stop+0x110/0x110
ret_from_fork+0x35/0x40
Fixes: 1f6a2c6d9f121 ("x86/numa_emulation: Introduce uniform split capability")
Signed-off-by: Dave Jiang <dave.ji...@intel.com>
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Tested-by: Alexander Duyck <alexander.h.du...@linux.intel.com>
Reviewed-by: Dave Hansen <dave.han...@linux.intel.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: sta...@vger.kernel.org
Link:
https://lkml.kernel.org/r/154049911459.2685845.9210186007479774286.st...@dwillia2-desk3.amr.corp.intel.com
---
arch/x86/mm/numa_emulation.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c
index b54d52a2d00a..d71d72cf6c66 100644
--- a/arch/x86/mm/numa_emulation.c
+++ b/arch/x86/mm/numa_emulation.c
@@ -400,9 +400,17 @@ void __init numa_emulation(struct numa_meminfo
*numa_meminfo, int numa_dist_cnt)
n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
ret = -1;
for_each_node_mask(i, physnode_mask) {
+ /*
+ * The reason we pass in blk[0] is due to
+ * numa_remove_memblk_from() called by
+ * emu_setup_memblk() will delete entry 0
+ * and then move everything else up in the pi.blk
+ * array. Therefore we should always be looking
+ * at blk[0].
+ */
ret = split_nodes_size_interleave_uniform(&ei, &pi,
- pi.blk[i].start, pi.blk[i].end, 0,
- n, &pi.blk[i], nid);
+ pi.blk[0].start, pi.blk[0].end, 0,
+ n, &pi.blk[0], nid);
if (ret < 0)
break;
if (ret < n) {
