(Just back from the summer holiday) Sorry for the late reply.
On 10/08/2024 06:38, Dan Williams wrote: > I notice this patch is not upstream yet. Let's try to get it over the > goal line. > > Li Zhijian wrote: >> The leakage would happen when create_namespace_pmem() meets an invalid >> label which gets failure in validating isetcookie. > > I would rewrite this as: > > "scan_labels() leaks memory when label scanning fails and it falls back > to just creating a default "seed" namespace for userspace to configure. > Root can force the kernel to leak memory." It sounds good to me. > > ...then a distribution developer knows the urgency to backport this fix. > >> Try to resuse the devs that may have already been allocated with size >> (2 * sizeof(dev)) previously. > > Rather than conditionally reallocating I think it would be better to > unconditionally allocate the minimum, something like: Okay, I will update it in V3. > > diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c > index d6d558f94d6b..1c38c93bee21 100644 > --- a/drivers/nvdimm/namespace_devs.c > +++ b/drivers/nvdimm/namespace_devs.c > @@ -1937,12 +1937,16 @@ static int cmp_dpa(const void *a, const void *b) > static struct device **scan_labels(struct nd_region *nd_region) > { > int i, count = 0; > - struct device *dev, **devs = NULL; > + struct device *dev, **devs; > struct nd_label_ent *label_ent, *e; > struct nd_mapping *nd_mapping = &nd_region->mapping[0]; > struct nvdimm_drvdata *ndd = to_ndd(nd_mapping); > resource_size_t map_end = nd_mapping->start + nd_mapping->size - 1; > > + devs = kcalloc(2, sizeof(dev), GFP_KERNEL); > + if (!devs) > + return NULL; > + > /* "safe" because create_namespace_pmem() might list_move() > label_ent */ > list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) { > struct nd_namespace_label *nd_label = label_ent->label; > @@ -1961,12 +1965,14 @@ static struct device **scan_labels(struct nd_region > *nd_region) > goto err; > if (i < count) > continue; > - __devs = kcalloc(count + 2, sizeof(dev), GFP_KERNEL); > - if (!__devs) > - goto err; > - memcpy(__devs, devs, sizeof(dev) * count); > - kfree(devs); > - devs = __devs; > + if (count) { > + __devs = kcalloc(count + 2, sizeof(dev), GFP_KERNEL); > + if (!__devs) > + goto err; > + memcpy(__devs, devs, sizeof(dev) * count); > + kfree(devs); > + devs = __devs; > + } > > dev = create_namespace_pmem(nd_region, nd_mapping, nd_label); > if (IS_ERR(dev)) { > @@ -1994,10 +2000,6 @@ static struct device **scan_labels(struct nd_region > *nd_region) > /* Publish a zero-sized namespace for userspace to > configure. */ > nd_mapping_free_labels(nd_mapping); > > - devs = kcalloc(2, sizeof(dev), GFP_KERNEL); > - if (!devs) > - goto err; > - > nspm = kzalloc(sizeof(*nspm), GFP_KERNEL); > if (!nspm) > goto err; > @@ -2036,12 +2038,10 @@ static struct device **scan_labels(struct nd_region > *nd_region) > return devs; > > err: > - if (devs) { > - for (i = 0; devs[i]; i++) > - namespace_pmem_release(devs[i]); > - kfree(devs); > - } > - return NULL; > + for (i = 0; devs[i]; i++) > + namespace_pmem_release(devs[i]); > + kfree(devs); > + return NULL; > } > > static struct device **create_namespaces(struct nd_region *nd_region) > > >> A kmemleak reports: >> unreferenced object 0xffff88800dda1980 (size 16): >> comm "kworker/u10:5", pid 69, jiffies 4294671781 >> hex dump (first 16 bytes): >> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> backtrace (crc 0): >> [<00000000c5dea560>] __kmalloc+0x32c/0x470 >> [<000000009ed43c83>] nd_region_register_namespaces+0x6fb/0x1120 >> [libnvdimm] >> [<000000000e07a65c>] nd_region_probe+0xfe/0x210 [libnvdimm] >> [<000000007b79ce5f>] nvdimm_bus_probe+0x7a/0x1e0 [libnvdimm] >> [<00000000a5f3da2e>] really_probe+0xc6/0x390 >> [<00000000129e2a69>] __driver_probe_device+0x78/0x150 >> [<000000002dfed28b>] driver_probe_device+0x1e/0x90 >> [<00000000e7048de2>] __device_attach_driver+0x85/0x110 >> [<0000000032dca295>] bus_for_each_drv+0x85/0xe0 >> [<00000000391c5a7d>] __device_attach+0xbe/0x1e0 >> [<0000000026dabec0>] bus_probe_device+0x94/0xb0 >> [<00000000c590d936>] device_add+0x656/0x870 >> [<000000003d69bfaa>] nd_async_device_register+0xe/0x50 [libnvdimm] >> [<000000003f4c52a4>] async_run_entry_fn+0x2e/0x110 >> [<00000000e201f4b0>] process_one_work+0x1ee/0x600 >> [<000000006d90d5a9>] worker_thread+0x183/0x350 > > Thanks for including this. > > With the above changes you can add: > > Reviewed-by: Dan Williams <dan.j.willi...@intel.com>