> On Jul 31, 2019, at 5:53 AM, Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > On Tue, Jul 30, 2019 at 04:22:37PM -0400, Qian Cai wrote: >> On Tue, 2019-07-30 at 12:57 -0700, Andrew Morton wrote: >>> On Sat, 27 Jul 2019 14:23:33 +0100 Catalin Marinas <catalin.marinas@xxxxxxx> >>>> --- a/Documentation/admin-guide/kernel-parameters.txt >>>> +++ b/Documentation/admin-guide/kernel-parameters.txt >>>> @@ -2011,6 +2011,12 @@ >>>> Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, >>>> the default is off. >>>> >>>> + kmemleak.mempool= >>>> + [KNL] Boot-time tuning of the minimum kmemleak >>>> + metadata pool size. >>>> + Format: <int> >>>> + Default: NR_CPUS * 4 >>>> + >> >> Catalin, BTW, it is right now unable to handle a large size. I tried to reserve >> 64M (kmemleak.mempool=67108864), >> >> [ 0.039254][ T0] WARNING: CPU: 0 PID: 0 at mm/page_alloc.c:4707 __alloc_pages_nodemask+0x3b8/0x1780 > [...] >> [ 0.039646][ T0] NIP [c000000000395038] __alloc_pages_nodemask+0x3b8/0x1780 >> [ 0.039693][ T0] LR [c0000000003d9320] kmalloc_large_node+0x100/0x1a0 >> [ 0.039727][ T0] Call Trace: >> [ 0.039795][ T0] [c00000000170fc80] [c0000000003e5080] __kmalloc_node+0x520/0x890 >> [ 0.039816][ T0] [c00000000170fd20] [c0000000002e9544] mempool_init_node+0xb4/0x1e0 >> [ 0.039836][ T0] [c00000000170fd80] [c0000000002e975c] mempool_create_node+0xcc/0x150 >> [ 0.039857][ T0] [c00000000170fdf0] [c000000000b2a730] kmemleak_init+0x16c/0x54c >> [ 0.039878][ T0] [c00000000170fef0] [c000000000ae460c] start_kernel+0x69c/0x7cc >> [ 0.039908][ T0] [c00000000170ff90] [c00000000000a7d4] start_here_common+0x1c/0x434 > [...] >> [ 0.040100][ T0] kmemleak: Kernel memory leak detector disabled > > It looks like the mempool cannot be created. 64M objects means a > kmalloc(512MB) for the pool array in mempool_init_node(), so that hits > the MAX_ORDER warning in __alloc_pages_nodemask(). > > Maybe the mempool tunable won't help much for your case if you need so > many objects. It's still worth having a mempool for kmemleak but we > could look into changing the refill logic while keeping the original > size constant (say 1024 objects). Actually, kmemleak.mempool=524288 works quite well on systems I have here. This is more of making the code robust by error-handling a large value without the NULL-ptr-deref below. Maybe simply just validate the value by adding upper bound to not trigger that warning with MAX_ORDER. > >> [ 16.192449][ T1] BUG: Unable to handle kernel data access at 0xffffffffffffb2aa > > This doesn't seem kmemleak related from the trace. This only happens when passing a large kmemleak.mempool, e.g., 64M [ 16.193126][ T1] NIP [c000000000b2a2fc] log_early+0x8/0x160 [ 16.193153][ T1] LR [c0000000003e6e48] kmem_cache_free+0x428/0x740 [ 16.193190][ T1] Call Trace: [ 16.193213][ T1] [c00000002aaefc60] [0000000000000366] 0x366 (unreliable) [ 16.193243][ T1] [c00000002aaefd00] [c0000000003c9270] __mpol_put+0x50/0x70 [ 16.193272][ T1] [c00000002aaefd20] [c0000000003c9488] do_set_mempolicy+0x108/0x170 [ 16.193314][ T1] [c00000002aaefdb0] [c000000000010434] kernel_init+0x64/0x150 [ 16.193363][ T1] [c00000002aaefe20] [c00000000000b1cc] ret_from_kernel_thread+0x5c/0x70 # ./scripts/faddr2line vmlinux log_early+0x8/0x160 log_early+0x8/0x160: log_early at mm/kmemleak.c:859
