commit 6f42193fd86e ("memremap: don't use a separate devm action for
devmap_managed_enable_get") changed the static key updates such that we
now call devmap_managed_enable_put() without doing the equivalent
devmap_managed_enable_get().devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap types too. This results in the below warning when switching between system-ram and devdax mode for devdax namespace. jump label: negative count! WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 Modules linked in: .... NIP [c000000000433318] static_key_slow_try_dec+0x88/0xa0 LR [c000000000433314] static_key_slow_try_dec+0x84/0xa0 Call Trace: [c000000025c1f660] [c000000000433314] static_key_slow_try_dec+0x84/0xa0 (unreliable) [c000000025c1f6d0] [c000000000433664] __static_key_slow_dec_cpuslocked+0x34/0xd0 [c000000025c1f700] [c0000000004337a4] static_key_slow_dec+0x54/0xf0 [c000000025c1f770] [c00000000059c49c] memunmap_pages+0x36c/0x500 [c000000025c1f820] [c000000000d91d10] devm_action_release+0x30/0x50 [c000000025c1f840] [c000000000d92e34] release_nodes+0x2f4/0x3e0 [c000000025c1f8f0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 [c000000025c1f930] [c000000000d883a4] bus_remove_device+0x124/0x210 [c000000025c1f9b0] [c000000000d80ef4] device_del+0x1d4/0x530 [c000000025c1fa70] [c000000000e341e8] unregister_dev_dax+0x48/0xe0 [c000000025c1fae0] [c000000000d91d10] devm_action_release+0x30/0x50 [c000000025c1fb00] [c000000000d92e34] release_nodes+0x2f4/0x3e0 [c000000025c1fbb0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 [c000000025c1fbf0] [c000000000d87000] unbind_store+0x130/0x170 [c000000025c1fc30] [c000000000d862a0] drv_attr_store+0x40/0x60 [c000000025c1fc50] [c0000000006d316c] sysfs_kf_write+0x6c/0xb0 [c000000025c1fc90] [c0000000006d2328] kernfs_fop_write+0x118/0x280 [c000000025c1fce0] [c0000000005a79f8] vfs_write+0xe8/0x2a0 [c000000025c1fd30] [c0000000005a7d94] ksys_write+0x84/0x140 [c000000025c1fd80] [c00000000003a430] system_call_exception+0x120/0x270 [c000000025c1fe20] [c00000000000c540] system_call_common+0xf0/0x27c Cc: Christoph Hellwig <[email protected]> Cc: Dan Williams <[email protected]> Cc: Sachin Sant <[email protected]> Cc: [email protected] Cc: Ira Weiny <[email protected]> Cc: Jason Gunthorpe <[email protected]> Signed-off-by: Aneesh Kumar K.V <[email protected]> --- mm/memremap.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/mm/memremap.c b/mm/memremap.c index 73a206d0f645..d4402ff3e467 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -158,6 +158,16 @@ void memunmap_pages(struct dev_pagemap *pgmap) { unsigned long pfn; int i; + bool need_devmap_managed = false; + + switch (pgmap->type) { + case MEMORY_DEVICE_PRIVATE: + case MEMORY_DEVICE_FS_DAX: + need_devmap_managed = true; + break; + default: + break; + } dev_pagemap_kill(pgmap); for (i = 0; i < pgmap->nr_range; i++) @@ -169,7 +179,8 @@ void memunmap_pages(struct dev_pagemap *pgmap) pageunmap_range(pgmap, i); WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); - devmap_managed_enable_put(); + if (need_devmap_managed) + devmap_managed_enable_put(); } EXPORT_SYMBOL_GPL(memunmap_pages); @@ -307,7 +318,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) .pgprot = PAGE_KERNEL, }; const int nr_range = pgmap->nr_range; - bool need_devmap_managed = true; + bool need_devmap_managed = false; int error, i; if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) @@ -327,6 +338,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "Missing owner\n"); return ERR_PTR(-EINVAL); } + need_devmap_managed = true; break; case MEMORY_DEVICE_FS_DAX: if (!IS_ENABLED(CONFIG_ZONE_DEVICE) || @@ -334,13 +346,12 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "File system DAX not supported\n"); return ERR_PTR(-EINVAL); } + need_devmap_managed = true; break; case MEMORY_DEVICE_GENERIC: - need_devmap_managed = false; break; case MEMORY_DEVICE_PCI_P2PDMA: params.pgprot = pgprot_noncached(params.pgprot); - need_devmap_managed = false; break; default: WARN(1, "Invalid pgmap type %d\n", pgmap->type); -- 2.26.2 _______________________________________________ Linux-nvdimm mailing list -- [email protected] To unsubscribe send an email to [email protected]
