On Sat 26-05-18 09:14:35, Mathieu Malaterre wrote:
> Hi Michal,
>
> For the last couple of days, I am seeing the following appearing in
> dmesg (*). I am a happy kmemleak user on an oldish Mac Mini G4
> (ppc32), it has been working great. What does this new warning checks:
>
> /*
> * All existing users of the __GFP_NOFAIL are blockable, so warn
> * of any new users that actually require GFP_NOWAIT
> */
> if (WARN_ON_ONCE(!can_direct_reclaim))
> goto fail;
Interesting. Where does this path get GFP_NOFAIL from? I am looking at
the current upstream code and
get_swap_bio(GFP_NOIO)
bio_alloc(gfp_mask)
bio_alloc_bioset(gfp_mask)
mempool_alloc(gfp_msk & ~__GFP_DIRECT_RECLAIM)
mempool_alloc does play some tricks with the gfp_mask but it doesn't add
GFP_NOFAIL AFAICS.
> Thanks,
>
> (*)
> [ 269.038911] WARNING: CPU: 0 PID: 21 at ../mm/page_alloc.c:4258
> __alloc_pages_nodemask+0xa88/0xfec
[...]
> [ 269.039118] NIP [c020e8f8] __alloc_pages_nodemask+0xa88/0xfec
> [ 269.039124] LR [c020e2e0] __alloc_pages_nodemask+0x470/0xfec
> [ 269.039128] Call Trace:
> [ 269.039136] [dde3b750] [c020e2e0] __alloc_pages_nodemask+0x470/0xfec (unreliable)
> [ 269.039146] [dde3b820] [c0288c14] new_slab+0x53c/0x970
> [ 269.039155] [dde3b880] [c028b61c] ___slab_alloc.constprop.23+0x28c/0x468
> [ 269.039163] [dde3b920] [c028c754] kmem_cache_alloc+0x290/0x3dc
> [ 269.039177] [dde3b990] [c02a6030] create_object+0x50/0x3d0
> [ 269.039185] [dde3b9e0] [c028c7a8] kmem_cache_alloc+0x2e4/0x3dc
> [ 269.039193] [dde3ba50] [c0200f88] mempool_alloc+0x7c/0x164
> [ 269.039205] [dde3bab0] [c03e33c0] bio_alloc_bioset+0x130/0x298
> [ 269.039216] [dde3baf0] [c0278694] get_swap_bio+0x34/0xe8
> [ 269.039223] [dde3bb30] [c0278fb4] __swap_writepage+0x22c/0x644
> [ 269.039237] [dde3bbb0] [c022528c] pageout.isra.13+0x238/0x52c
> [ 269.039246] [dde3bc10] [c02288a0] shrink_page_list+0x9d4/0x1768
> [ 269.039254] [dde3bcb0] [c022a264] shrink_inactive_list+0x2c4/0xa34
> [ 269.039262] [dde3bd40] [c022b454] shrink_node_memcg+0x344/0xe34
> [ 269.039270] [dde3bde0] [c022c068] shrink_node+0x124/0x73c
> [ 269.039277] [dde3be50] [c022d78c] kswapd+0x318/0xb2c
> [ 269.039291] [dde3bf10] [c008e264] kthread+0x138/0x1f0
> [ 269.039300] [dde3bf40] [c001b2e4] ret_from_kernel_thread+0x5c/0x64
> [ 269.039304] Instruction dump:
> [ 269.039311] 7f44d378 7fa3eb78 4802bd95 4bfff9f4 485d7309 4bfff998 7f03c378 7fc5f378
> [ 269.039326] 7f44d378 4802bd79 7c781b78 4bfffd48 <0fe00000> 8081002c 3ca0c08b 7fe6fb78
> [ 269.039343] ---[ end trace c255e24f03e28d77 ]---
> [ 269.039351] kmemleak: Cannot allocate a kmemleak_object structure
> [ 269.039373] kmemleak: Kernel memory leak detector disabled
> [ 269.039412] kmemleak: Automatic memory scanning thread ended
--
Michal Hocko
SUSE Labs
