Messages in this thread | | | Date | Wed, 2 Jun 2021 08:18:37 +0200 | From | Greg KH <> | Subject | Re: [PATCH 1/2] topology: use bin_attribute to avoid buff overflow |
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On Wed, Jun 02, 2021 at 02:14:49PM +0800, tiantao (H) wrote: > > 在 2021/6/1 12:58, Greg KH 写道: > > On Tue, Jun 01, 2021 at 10:56:49AM +0800, Tian Tao wrote: > > > Reading sys/devices/system/cpu/cpuX/topology/ returns cpu topology. > > > However, the size of this file is limited to PAGE_SIZE because of the > > > limitation for sysfs attribute. so we use bin_attribute instead of > > > attribute to avoid NR_CPUS too big to cause buff overflow. > > > > > > This patch is based on the following discussion. > > > https://www.spinics.net/lists/linux-doc/msg95921.html > > Please use lore.kernel.org for links as we have no control over other > > sites to ensure that they will work in the future. Use the message id > > in the link as well, so that if something were to happen to lore, we can > > figure it out. > > > > Also, you are modifying a bunch of different files here, do you mean to > > do it for all of them? > > > > > Signed-off-by: Tian Tao <tiantao6@hisilicon.com> > > > Cc: Andrew Morton <akpm@linux-foundation.org> > > > Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > > Cc: "Rafael J. Wysocki" <rafael@kernel.org> > > > --- > > > drivers/base/topology.c | 115 ++++++++++++++++++++++++++---------------------- > > > include/linux/bitmap.h | 3 ++ > > > include/linux/cpumask.h | 25 +++++++++++ > > > lib/bitmap.c | 34 ++++++++++++++ > > > 4 files changed, 125 insertions(+), 52 deletions(-) > > > > > > diff --git a/drivers/base/topology.c b/drivers/base/topology.c > > > index 4d254fc..013edbb 100644 > > > --- a/drivers/base/topology.c > > > +++ b/drivers/base/topology.c > > > @@ -21,25 +21,27 @@ static ssize_t name##_show(struct device *dev, \ > > > return sysfs_emit(buf, "%d\n", topology_##name(dev->id)); \ > > > } > > > -#define define_siblings_show_map(name, mask) \ > > > -static ssize_t name##_show(struct device *dev, \ > > > - struct device_attribute *attr, char *buf) \ > > > -{ \ > > > - return cpumap_print_to_pagebuf(false, buf, topology_##mask(dev->id));\ > > > +#define define_siblings_read_func(name, mask) \ > > > +static ssize_t name##_read(struct file *file, struct kobject *kobj, \ > > > + struct bin_attribute *attr, char *buf, \ > > > + loff_t off, size_t count) \ > > > +{ \ > > > + struct device *dev = kobj_to_dev(kobj); \ > > > + \ > > > + return cpumap_print_to_buf(false, buf, topology_##mask(dev->id), \ > > > + off, count); \ > > > +} \ > > > + \ > > > +static ssize_t name##_list_read(struct file *file, struct kobject *kobj, \ > > > + struct bin_attribute *attr, char *buf, \ > > > + loff_t off, size_t count) \ > > > +{ \ > > > + struct device *dev = kobj_to_dev(kobj); \ > > > + \ > > > + return cpumap_print_to_buf(true, buf, topology_##mask(dev->id), \ > > > + off, count); \ > > > } > > > -#define define_siblings_show_list(name, mask) \ > > > -static ssize_t name##_list_show(struct device *dev, \ > > > - struct device_attribute *attr, \ > > > - char *buf) \ > > > -{ \ > > > - return cpumap_print_to_pagebuf(true, buf, topology_##mask(dev->id));\ > > > -} > > > - > > > -#define define_siblings_show_func(name, mask) \ > > > - define_siblings_show_map(name, mask); \ > > > - define_siblings_show_list(name, mask) > > > - > > > define_id_show_func(physical_package_id); > > > static DEVICE_ATTR_RO(physical_package_id); > > > @@ -49,71 +51,80 @@ static DEVICE_ATTR_RO(die_id); > > > define_id_show_func(core_id); > > > static DEVICE_ATTR_RO(core_id); > > > -define_siblings_show_func(thread_siblings, sibling_cpumask); > > > -static DEVICE_ATTR_RO(thread_siblings); > > > -static DEVICE_ATTR_RO(thread_siblings_list); > > > +define_siblings_read_func(thread_siblings, sibling_cpumask); > > > +static BIN_ATTR_RO(thread_siblings, 0); > > > +static BIN_ATTR_RO(thread_siblings_list, 0); > > > -define_siblings_show_func(core_cpus, sibling_cpumask); > > > -static DEVICE_ATTR_RO(core_cpus); > > > -static DEVICE_ATTR_RO(core_cpus_list); > > > +define_siblings_read_func(core_cpus, sibling_cpumask); > > > +static BIN_ATTR_RO(core_cpus, 0); > > > +static BIN_ATTR_RO(core_cpus_list, 0); > > > -define_siblings_show_func(core_siblings, core_cpumask); > > > -static DEVICE_ATTR_RO(core_siblings); > > > -static DEVICE_ATTR_RO(core_siblings_list); > > > +define_siblings_read_func(core_siblings, core_cpumask); > > > +static BIN_ATTR_RO(core_siblings, 0); > > > +static BIN_ATTR_RO(core_siblings_list, 0); > > > -define_siblings_show_func(die_cpus, die_cpumask); > > > -static DEVICE_ATTR_RO(die_cpus); > > > -static DEVICE_ATTR_RO(die_cpus_list); > > > +define_siblings_read_func(die_cpus, die_cpumask); > > > +static BIN_ATTR_RO(die_cpus, 0); > > > +static BIN_ATTR_RO(die_cpus_list, 0); > > > -define_siblings_show_func(package_cpus, core_cpumask); > > > -static DEVICE_ATTR_RO(package_cpus); > > > -static DEVICE_ATTR_RO(package_cpus_list); > > > +define_siblings_read_func(package_cpus, core_cpumask); > > > +static BIN_ATTR_RO(package_cpus, 0); > > > +static BIN_ATTR_RO(package_cpus_list, 0); > > > #ifdef CONFIG_SCHED_BOOK > > > define_id_show_func(book_id); > > > static DEVICE_ATTR_RO(book_id); > > > -define_siblings_show_func(book_siblings, book_cpumask); > > > -static DEVICE_ATTR_RO(book_siblings); > > > -static DEVICE_ATTR_RO(book_siblings_list); > > > +define_siblings_read_func(book_siblings, book_cpumask); > > > +static BIN_ATTR_RO(book_siblings, 0); > > > +static BIN_ATTR_RO(book_siblings_list, 0); > > > #endif > > > #ifdef CONFIG_SCHED_DRAWER > > > define_id_show_func(drawer_id); > > > static DEVICE_ATTR_RO(drawer_id); > > > -define_siblings_show_func(drawer_siblings, drawer_cpumask); > > > -static DEVICE_ATTR_RO(drawer_siblings); > > > -static DEVICE_ATTR_RO(drawer_siblings_list); > > > +define_siblings_read_func(drawer_siblings, drawer_cpumask); > > > +static BIN_ATTR_RO(drawer_siblings, 0); > > > +static BIN_ATTR_RO(drawer_siblings_list, 0); > > > #endif > > > +static struct bin_attribute *bin_attrs[] = { > > > + &bin_attr_core_cpus, > > > + &bin_attr_core_cpus_list, > > > + &bin_attr_thread_siblings, > > > + &bin_attr_thread_siblings_list, > > > + &bin_attr_core_siblings, > > > + &bin_attr_core_siblings_list, > > > + &bin_attr_die_cpus, > > > + &bin_attr_die_cpus_list, > > > + &bin_attr_package_cpus, > > > + &bin_attr_package_cpus_list, > > > +#ifdef CONFIG_SCHED_BOOK > > > + &bin_attr_book_siblings, > > > + &bin_attr_book_siblings_list, > > > +#endif > > > +#ifdef CONFIG_SCHED_DRAWER > > > + &bin_attr_drawer_siblings, > > > + &bin_attr_drawer_siblings_list, > > > +#endif > > > + NULL, > > > +}; > > > + > > > static struct attribute *default_attrs[] = { > > > &dev_attr_physical_package_id.attr, > > > &dev_attr_die_id.attr, > > > &dev_attr_core_id.attr, > > > - &dev_attr_thread_siblings.attr, > > > - &dev_attr_thread_siblings_list.attr, > > > - &dev_attr_core_cpus.attr, > > > - &dev_attr_core_cpus_list.attr, > > > - &dev_attr_core_siblings.attr, > > > - &dev_attr_core_siblings_list.attr, > > > - &dev_attr_die_cpus.attr, > > > - &dev_attr_die_cpus_list.attr, > > > - &dev_attr_package_cpus.attr, > > > - &dev_attr_package_cpus_list.attr, > > > #ifdef CONFIG_SCHED_BOOK > > > &dev_attr_book_id.attr, > > > - &dev_attr_book_siblings.attr, > > > - &dev_attr_book_siblings_list.attr, > > > #endif > > > #ifdef CONFIG_SCHED_DRAWER > > > &dev_attr_drawer_id.attr, > > > - &dev_attr_drawer_siblings.attr, > > > - &dev_attr_drawer_siblings_list.attr, > > > #endif > > > NULL > > > }; > > > static const struct attribute_group topology_attr_group = { > > > .attrs = default_attrs, > > > + .bin_attrs = bin_attrs, > > > .name = "topology" > > > }; > > > diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h > > > index 70a9324..bc401bd9b 100644 > > > --- a/include/linux/bitmap.h > > > +++ b/include/linux/bitmap.h > > > @@ -219,6 +219,9 @@ extern unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int > > > extern int bitmap_print_to_pagebuf(bool list, char *buf, > > > const unsigned long *maskp, int nmaskbits); > > > +extern int bitmap_print_to_buf(bool list, char *buf, > > > + const unsigned long *maskp, int nmaskbits, loff_t off, size_t count); > > > + > > > #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) > > > #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) > > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > > > index 383684e..e4810b3e 100644 > > > --- a/include/linux/cpumask.h > > > +++ b/include/linux/cpumask.h > > > @@ -928,6 +928,31 @@ cpumap_print_to_pagebuf(bool list, char *buf, const struct cpumask *mask) > > > nr_cpu_ids); > > > } > > > +/** > > > + * cpumap_print_to_buf - copies the cpumask into the buffer either > > > + * as comma-separated list of cpus or hex values of cpumask > > > + * @list: indicates whether the cpumap must be list > > > + * @mask: the cpumask to copy > > > + * @buf: the buffer to copy into > > > + * @off: the offset that buffer to copy into > > > + * @count: the count thatbuffer to copy into > > > + * > > > + * the role of cpumap_print_to_buf and cpumap_print_to_pagebuf is > > > + * the same, the difference is that the second parameter of > > > + * bitmap_print_to_buf can be more than one pagesize. > > > + * > > > + * Returns the length of the (null-terminated) @buf string, zero if > > > + * nothing is copied. > > > + */ > > > + > > > +static inline ssize_t > > > +cpumap_print_to_buf(bool list, char *buf, const struct cpumask *mask, > > > + loff_t off, size_t count) > > > +{ > > > + return bitmap_print_to_buf(list, buf, cpumask_bits(mask), > > > + nr_cpu_ids, off, count); > > > +} > > > + > > > #if NR_CPUS <= BITS_PER_LONG > > > #define CPU_MASK_ALL \ > > > (cpumask_t) { { \ > > > diff --git a/lib/bitmap.c b/lib/bitmap.c > > > index 75006c4..5bf89f1 100644 > > > --- a/lib/bitmap.c > > > +++ b/lib/bitmap.c > > > @@ -460,6 +460,40 @@ int bitmap_parse_user(const char __user *ubuf, > > > EXPORT_SYMBOL(bitmap_parse_user); > > > /** > > > + * bitmap_print_to_buf - convert bitmap to list or hex format ASCII string > > > + * @list: indicates whether the bitmap must be list > > > + * @buf: page aligned buffer into which string is placed > > > + * @maskp: pointer to bitmap to convert > > > + * @nmaskbits: size of bitmap, in bits > > > + * @off: offset in buf > > > + * @count: count that already output > > > + * > > > + * the role of bitmap_print_to_buf and bitmap_print_to_pagebuf is > > > + * the same, the difference is that the second parameter of > > > + * bitmap_print_to_buf can be more than one pagesize. > > > + */ > > > +int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp, > > > + int nmaskbits, loff_t off, size_t count) > > > +{ > > > + int len, size; > > > + void *data; > > > + char *fmt = list ? "%*pbl\n" : "%*pb\n"; > > > + > > > + len = snprintf(NULL, 0, fmt, nmaskbits, maskp); > > > + > > > + data = kvmalloc(len+1, GFP_KERNEL); > > > + if (!data) > > > + return -ENOMEM; > > > + > > > + size = scnprintf(data, len+1, fmt, nmaskbits, maskp); > > > + size = memory_read_from_buffer(buf, count, &off, data, size); > > > + kvfree(data); > > > + > > > + return size; > > Why is this so different from bitmap_print_to_pagebuf()? Can't you just > > use this function as the "real" function and then change > > bitmap_print_to_pagebuf() to call it with a size of PAGE_SIZE? > > Do you mean do following change, is that correct? :-)
Maybe, it is whitespace corrupted, and it still feels like this function is much bigger than it needs to be given the function it is replacing is only a simple sprintf() call.
> +int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp, > + int nmaskbits, loff_t off, size_t count) > +{ > + int len, size; > + void *data; > + const char *fmt = list ? "%*pbl\n" : "%*pb\n"; > + > + if (off == LLONG_MAX && count == PAGE_SIZE - offset_in_page(buf)) > + return scnprintf(buf, count, fmt, nmaskbits, maskp); > + > + len = snprintf(NULL, 0, fmt, nmaskbits, maskp); > + > + data = kvmalloc(len+1, GFP_KERNEL);
Why do you need to allocate more memory? And why kvmalloc()?
> + if (!data) > + return -ENOMEM; > + > + size = scnprintf(data, len+1, fmt, nmaskbits, maskp); > + > + size = memory_read_from_buffer(buf, count, &off, data, size); > + kvfree(data); > + > + return size; > +} > +EXPORT_SYMBOL(bitmap_print_to_buf);
thanks,
greg k-h
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