Commit 19051c5035d217e572672a2ca9db06c1cef50e9b
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8882b39421
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mm: bdi: fix race in bdi_class device creation
There is a race from when a device is created with device_create() and then the drvdata is set with a call to dev_set_drvdata() in which a sysfs file could be open, yet the drvdata will be NULL, causing all sorts of bad things to happen. This patch fixes the problem by using the new function, device_create_vargs(). Many thanks to Arthur Jones <ajones@riverbed.com> for reporting the bug, and testing patches out. Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Arthur Jones <ajones@riverbed.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Showing 1 changed file with 2 additions and 10 deletions Side-by-side Diff
mm/backing-dev.c
| ... | ... | @@ -172,30 +172,22 @@ |
| 172 | 172 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
| 173 | 173 | const char *fmt, ...) |
| 174 | 174 | { |
| 175 | - char *name; | |
| 176 | 175 | va_list args; |
| 177 | 176 | int ret = 0; |
| 178 | 177 | struct device *dev; |
| 179 | 178 | |
| 180 | 179 | va_start(args, fmt); |
| 181 | - name = kvasprintf(GFP_KERNEL, fmt, args); | |
| 180 | + dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args); | |
| 182 | 181 | va_end(args); |
| 183 | - | |
| 184 | - if (!name) | |
| 185 | - return -ENOMEM; | |
| 186 | - | |
| 187 | - dev = device_create(bdi_class, parent, MKDEV(0, 0), name); | |
| 188 | 182 | if (IS_ERR(dev)) { |
| 189 | 183 | ret = PTR_ERR(dev); |
| 190 | 184 | goto exit; |
| 191 | 185 | } |
| 192 | 186 | |
| 193 | 187 | bdi->dev = dev; |
| 194 | - dev_set_drvdata(bdi->dev, bdi); | |
| 195 | - bdi_debug_register(bdi, name); | |
| 188 | + bdi_debug_register(bdi, dev_name(dev)); | |
| 196 | 189 | |
| 197 | 190 | exit: |
| 198 | - kfree(name); | |
| 199 | 191 | return ret; |
| 200 | 192 | } |
| 201 | 193 | EXPORT_SYMBOL(bdi_register); |