[PATCH 4.4 051/137] cifs: Ratelimit kernel log messages
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2016-02-24 04:14:31
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4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jamie Bainbridge <redacted> commit ec7147a99e33a9e4abad6fc6e1b40d15df045d53 upstream. Under some conditions, CIFS can repeatedly call the cifs_dbg() logging wrapper. If done rapidly enough, the console framebuffer can softlockup or "rcu_sched self-detected stall". Apply the built-in log ratelimiters to prevent such hangs. Signed-off-by: Jamie Bainbridge <redacted> Signed-off-by: Steve French <smfrench@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/cifs/cifs_debug.c | 2 +- fs/cifs/cifs_debug.h | 9 ++++----- 2 files changed, 5 insertions(+), 6 deletions(-)
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c@@ -50,7 +50,7 @@ void cifs_vfs_err(const char *fmt, ...) vaf.fmt = fmt; vaf.va = &args; - pr_err("CIFS VFS: %pV", &vaf); + pr_err_ratelimited("CIFS VFS: %pV", &vaf); va_end(args); } --- a/fs/cifs/cifs_debug.h +++ b/fs/cifs/cifs_debug.h
@@ -51,14 +51,13 @@ __printf(1, 2) void cifs_vfs_err(const c /* information message: e.g., configuration, major event */ #define cifs_dbg(type, fmt, ...) \ do { \ - if (type == FYI) { \ - if (cifsFYI & CIFS_INFO) { \ - pr_debug("%s: " fmt, __FILE__, ##__VA_ARGS__); \ - } \ + if (type == FYI && cifsFYI & CIFS_INFO) { \ + pr_debug_ratelimited("%s: " \ + fmt, __FILE__, ##__VA_ARGS__); \ } else if (type == VFS) { \ cifs_vfs_err(fmt, ##__VA_ARGS__); \ } else if (type == NOISY && type != 0) { \ - pr_debug(fmt, ##__VA_ARGS__); \ + pr_debug_ratelimited(fmt, ##__VA_ARGS__); \ } \ } while (0)