The simple attribute files do not accept a negative value since the commit 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()"), so we have to use a 64-bit value to write a negative value for a debugfs file created by debugfs_create_atomic_t().
This restores the previous behaviour by introducing DEFINE_DEBUGFS_ATTRIBUTE_SIGNED for a signed value.
Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()") Reported-by: Zhao Gongyi zhaogongyi@huawei.com Signed-off-by: Akinobu Mita akinobu.mita@gmail.com --- .../fault-injection/fault-injection.rst | 10 +++---- fs/debugfs/file.c | 28 +++++++++++++++---- include/linux/debugfs.h | 19 +++++++++++-- 3 files changed, 43 insertions(+), 14 deletions(-)
diff --git a/Documentation/fault-injection/fault-injection.rst b/Documentation/fault-injection/fault-injection.rst index 17779a2772e5..5f6454b9dbd4 100644 --- a/Documentation/fault-injection/fault-injection.rst +++ b/Documentation/fault-injection/fault-injection.rst @@ -83,9 +83,7 @@ configuration of fault-injection capabilities. - /sys/kernel/debug/fail*/times:
specifies how many times failures may happen at most. A value of -1 - means "no limit". Note, though, that this file only accepts unsigned - values. So, if you want to specify -1, you better use 'printf' instead - of 'echo', e.g.: $ printf %#x -1 > times + means "no limit".
- /sys/kernel/debug/fail*/space:
@@ -284,7 +282,7 @@ Application Examples echo Y > /sys/kernel/debug/$FAILTYPE/task-filter echo 10 > /sys/kernel/debug/$FAILTYPE/probability echo 100 > /sys/kernel/debug/$FAILTYPE/interval - printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times + echo -1 > /sys/kernel/debug/$FAILTYPE/times echo 0 > /sys/kernel/debug/$FAILTYPE/space echo 2 > /sys/kernel/debug/$FAILTYPE/verbose echo Y > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait @@ -338,7 +336,7 @@ Application Examples echo N > /sys/kernel/debug/$FAILTYPE/task-filter echo 10 > /sys/kernel/debug/$FAILTYPE/probability echo 100 > /sys/kernel/debug/$FAILTYPE/interval - printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times + echo -1 > /sys/kernel/debug/$FAILTYPE/times echo 0 > /sys/kernel/debug/$FAILTYPE/space echo 2 > /sys/kernel/debug/$FAILTYPE/verbose echo Y > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait @@ -369,7 +367,7 @@ Application Examples echo N > /sys/kernel/debug/$FAILTYPE/task-filter echo 100 > /sys/kernel/debug/$FAILTYPE/probability echo 0 > /sys/kernel/debug/$FAILTYPE/interval - printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times + echo -1 > /sys/kernel/debug/$FAILTYPE/times echo 0 > /sys/kernel/debug/$FAILTYPE/space echo 1 > /sys/kernel/debug/$FAILTYPE/verbose
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 950c63fa4d0b..38930d9b0bb7 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -378,8 +378,8 @@ ssize_t debugfs_attr_read(struct file *file, char __user *buf, } EXPORT_SYMBOL_GPL(debugfs_attr_read);
-ssize_t debugfs_attr_write(struct file *file, const char __user *buf, - size_t len, loff_t *ppos) +static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf, + size_t len, loff_t *ppos, bool is_signed) { struct dentry *dentry = F_DENTRY(file); ssize_t ret; @@ -387,12 +387,28 @@ ssize_t debugfs_attr_write(struct file *file, const char __user *buf, ret = debugfs_file_get(dentry); if (unlikely(ret)) return ret; - ret = simple_attr_write(file, buf, len, ppos); + if (is_signed) + ret = simple_attr_write_signed(file, buf, len, ppos); + else + ret = simple_attr_write(file, buf, len, ppos); debugfs_file_put(dentry); return ret; } + +ssize_t debugfs_attr_write(struct file *file, const char __user *buf, + size_t len, loff_t *ppos) +{ + return debugfs_attr_write_xsigned(file, buf, len, ppos, false); +} EXPORT_SYMBOL_GPL(debugfs_attr_write);
+ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf, + size_t len, loff_t *ppos) +{ + return debugfs_attr_write_xsigned(file, buf, len, ppos, true); +} +EXPORT_SYMBOL_GPL(debugfs_attr_write_signed); + static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode, struct dentry *parent, void *value, const struct file_operations *fops, @@ -738,11 +754,11 @@ static int debugfs_atomic_t_get(void *data, u64 *val) *val = atomic_read((atomic_t *)data); return 0; } -DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, +DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t, debugfs_atomic_t_get, debugfs_atomic_t_set, "%lld\n"); -DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, +DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, "%lld\n"); -DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, +DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, "%lld\n");
/** diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index f60674692d36..ea2d919fd9c7 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -45,7 +45,7 @@ struct debugfs_u32_array {
extern struct dentry *arch_debugfs_dir;
-#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt) \ +#define DEFINE_DEBUGFS_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, __is_signed) \ static int __fops ## _open(struct inode *inode, struct file *file) \ { \ __simple_attr_check_format(__fmt, 0ull); \ @@ -56,10 +56,16 @@ static const struct file_operations __fops = { \ .open = __fops ## _open, \ .release = simple_attr_release, \ .read = debugfs_attr_read, \ - .write = debugfs_attr_write, \ + .write = (__is_signed) ? debugfs_attr_write_signed : debugfs_attr_write, \ .llseek = no_llseek, \ }
+#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt) \ + DEFINE_DEBUGFS_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, false) + +#define DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(__fops, __get, __set, __fmt) \ + DEFINE_DEBUGFS_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, true) + typedef struct vfsmount *(*debugfs_automount_t)(struct dentry *, void *);
#if defined(CONFIG_DEBUG_FS) @@ -102,6 +108,8 @@ ssize_t debugfs_attr_read(struct file *file, char __user *buf, size_t len, loff_t *ppos); ssize_t debugfs_attr_write(struct file *file, const char __user *buf, size_t len, loff_t *ppos); +ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf, + size_t len, loff_t *ppos);
struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, struct dentry *new_dir, const char *new_name); @@ -254,6 +262,13 @@ static inline ssize_t debugfs_attr_write(struct file *file, return -ENODEV; }
+static inline ssize_t debugfs_attr_write_signed(struct file *file, + const char __user *buf, + size_t len, loff_t *ppos) +{ + return -ENODEV; +} + static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, struct dentry *new_dir, char *new_name) {