From c96900435fa9fdfd9702a60cd765bd85e380303e Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 9 Jan 2018 12:02:55 -0800 Subject: xfs: use %px for data pointers when debugging Starting with commit 57e734423ad ("vsprintf: refactor %pK code out of pointer"), the behavior of the raw '%p' printk format specifier was changed to print a 32-bit hash of the pointer value to avoid leaking kernel pointers into dmesg. For most situations that's good. This is /undesirable/ behavior when we're trying to debug XFS, however, so define a PTR_FMT that prints the actual pointer when we're in debug mode. Note that %p for tracepoints still prints the raw pointer, so in the long run we could consider rewriting some of these messages as tracepoints. Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner --- fs/xfs/xfs_linux.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'fs/xfs/xfs_linux.h') diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h index 74d3576c8043..bee51a14a906 100644 --- a/fs/xfs/xfs_linux.h +++ b/fs/xfs/xfs_linux.h @@ -291,4 +291,16 @@ static inline uint64_t howmany_64(uint64_t x, uint32_t y) #define XFS_IS_REALTIME_MOUNT(mp) (0) #endif +/* + * Starting in Linux 4.15, the %p (raw pointer value) printk modifier + * prints a hashed version of the pointer to avoid leaking kernel + * pointers into dmesg. If we're trying to debug the kernel we want the + * raw values, so override this behavior as best we can. + */ +#ifdef DEBUG +# define PTR_FMT "%px" +#else +# define PTR_FMT "%p" +#endif + #endif /* __XFS_LINUX__ */ -- cgit v1.2.3