On Wed, Jun 19, 2024 at 11:55:55AM +0200, James Gowans wrote: >If a driver/subsystem tries to do an allocation after the memblock >allocations have been freed and the memory handed to the buddy >allocator, it will not actually be legal to use that allocation: the >buddy allocator owns the memory. Currently this mis-use is handled by >the memblock function which does allocations and returns virtual >addresses by printing a warning and doing a kmalloc instead. However >the physical allocation function does not to do this check - callers of >the physical alloc function are unprotected against mis-use. > >Improve the error catching here by moving the check into the physical >allocation function which is used by the virtual addr allocation >function. > >Signed-off-by: James Gowans <jgowans@xxxxxxxxxx> >Cc: Mike Rapoport <rppt@xxxxxxxxxx> >Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >Cc: Alex Graf <graf@xxxxxxxxx> Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxx> >--- > >Notes: > Changes since v1: https://lore.kernel.org/all/20240614133016.134150-1-jgowans@xxxxxxxxxx/ > - Move this late usage check before alignment check > - Replace memblocks with memblock > > mm/memblock.c | 18 +++++++++++------- > 1 file changed, 11 insertions(+), 7 deletions(-) > >diff --git a/mm/memblock.c b/mm/memblock.c >index d09136e040d3..dbb3d700247e 100644 >--- a/mm/memblock.c >+++ b/mm/memblock.c >@@ -1451,6 +1451,17 @@ phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size, > if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n")) > nid = NUMA_NO_NODE; > >+ /* >+ * Detect any accidental use of these APIs after slab is ready, as at >+ * this moment memblock may be deinitialized already and its >+ * internal data may be destroyed (after execution of memblock_free_all) >+ */ >+ if (WARN_ON_ONCE(slab_is_available())) { >+ void *vaddr = kzalloc_node(size, GFP_NOWAIT, nid); >+ >+ return vaddr ? virt_to_phys(vaddr) : 0; >+ } >+ > if (!align) { > /* Can't use WARNs this early in boot on powerpc */ > dump_stack(); >@@ -1576,13 +1587,6 @@ static void * __init memblock_alloc_internal( > { > phys_addr_t alloc; > >- /* >- * Detect any accidental use of these APIs after slab is ready, as at >- * this moment memblock may be deinitialized already and its >- * internal data may be destroyed (after execution of memblock_free_all) >- */ >- if (WARN_ON_ONCE(slab_is_available())) >- return kzalloc_node(size, GFP_NOWAIT, nid); > > if (max_addr > memblock.current_limit) > max_addr = memblock.current_limit; >-- >2.34.1 > -- Wei Yang Help you, Help me
