4.19-stable review patch. If anyone has any objections, please let me know.
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From: Linus Torvalds torvalds@linux-foundation.org
commit a360f311f57a36e96d88fa8086b749159714dcd2 upstream.
This was attempted by using the dev_name in the slab cache name, but as Omar Sandoval pointed out, that can be an arbitrary string, eg something like "/dev/root". Which in turn trips verify_dirent_name(), which fails if a filename contains a slash.
So just make it use a sequence counter, and make it an atomic_t to avoid any possible races or locking issues.
Reported-and-tested-by: Omar Sandoval osandov@fb.com Link: https://lore.kernel.org/all/ZxafcO8KWMlXaeWE@telecaster.dhcp.thefacebook.com... Fixes: 79efebae4afc ("9p: Avoid creating multiple slab caches with the same name") Acked-by: Vlastimil Babka vbabka@suse.cz Cc: Dominique Martinet asmadeus@codewreck.org Cc: Thorsten Leemhuis regressions@leemhuis.info Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/9p/client.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/9p/client.c +++ b/net/9p/client.c @@ -1016,6 +1016,7 @@ error: struct p9_client *p9_client_create(const char *dev_name, char *options) { int err; + static atomic_t seqno = ATOMIC_INIT(0); struct p9_client *clnt; char *client_id; char *cache_name; @@ -1071,7 +1072,8 @@ struct p9_client *p9_client_create(const if (err) goto close_trans;
- cache_name = kasprintf(GFP_KERNEL, "9p-fcall-cache-%s", dev_name); + cache_name = kasprintf(GFP_KERNEL, + "9p-fcall-cache-%u", atomic_inc_return(&seqno)); if (!cache_name) { err = -ENOMEM; goto close_trans;