Re: [PATCH] powerpc/powernv: Fix idle state allocation corruption
From: Shreyas B Prabhu <hidden>
Date: 2015-05-20 17:28:48
On Wednesday 20 May 2015 10:43 PM, Jack Miller wrote:
pnv_alloc_idle_core_states is iterating over PACAs based on the configured maximum number of CPUs (NR_CPUS), but PACAs are only initialized up to nr_cpu_ids, so rein in loops to keep from overwriting adjacent memory.
Hi Jack, Jan Stancek has a patch fixing this (d52356e7f powerpc: fix memory corruption by pnv_alloc_idle_core_states). Thanks, Shreyas
quoted hunk ↗ jump to hunk
Signed-off-by: Jack Miller <redacted> --- arch/powerpc/platforms/powernv/setup.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-)diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c index ad0e32e..8e794b6 100644 --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c@@ -356,9 +356,8 @@ int pnv_save_sprs_for_winkle(void) static void pnv_alloc_idle_core_states(void) { - int i, j; - int nr_cores = cpu_nr_cores(); - u32 *core_idle_state; + u32 *core_idle_state = NULL; + int i, thread; /* * core_idle_state - First 8 bits track the idle state of each thread@@ -371,20 +370,17 @@ static void pnv_alloc_idle_core_states(void) * b. While the last thread in the core is saving the core state, it * prevents a different thread from waking up. */ - for (i = 0; i < nr_cores; i++) { - int first_cpu = i * threads_per_core; - int node = cpu_to_node(first_cpu); + for (i = 0; i < nr_cpu_ids; i++) { + thread = i % threads_per_core; - core_idle_state = kmalloc_node(sizeof(u32), GFP_KERNEL, node); - *core_idle_state = PNV_CORE_IDLE_THREAD_BITS; - - for (j = 0; j < threads_per_core; j++) { - int cpu = first_cpu + j; - - paca[cpu].core_idle_state_ptr = core_idle_state; - paca[cpu].thread_idle_state = PNV_THREAD_RUNNING; - paca[cpu].thread_mask = 1 << j; + if (thread == 0) { + core_idle_state = kmalloc_node(sizeof(u32), GFP_KERNEL, cpu_to_node(i)); + *core_idle_state = PNV_CORE_IDLE_THREAD_BITS; } + + paca[i].core_idle_state_ptr = core_idle_state; + paca[i].thread_idle_state = PNV_THREAD_RUNNING; + paca[i].thread_mask = 1 << thread; } update_subcore_sibling_mask();