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Commit efc55757 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Lachlan McIlroy
Browse files

[XFS] avoid memory allocations in xfs_fs_vcmn_err 



xfs_fs_vcmn_err can be called under a spinlock, but does a sleeping memory
allocation to create buffer for it's internal sprintf.  Fortunately it's
the only caller of icmn_err, so we can merge the two and have one single
static buffer and spinlock protecting it.  While we're at it make sure
we proper __attribute__ format annotations so that the compiler can detect
mismatched format strings.

Reported-by: default avatarAlexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarEric Sandeen <sandeen@sandeen.net>
Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
parent 9f6c92b9

fs/xfs/support/debug.c

+32 −5
Original line number Diff line number Diff line
@@ -18,6 +18,13 @@ 
#include <xfs.h>

#include "debug.h"



/* xfs_mount.h drags a lot of crap in, sorry.. */

#include "xfs_sb.h"

#include "xfs_inum.h"

#include "xfs_ag.h"

#include "xfs_dmapi.h"

#include "xfs_mount.h"



static char		message[1024];	/* keep it off the stack */

static DEFINE_SPINLOCK(xfs_err_lock);
@@ -55,22 +62,42 @@ cmn_err(register int level, char *fmt, ...) 
}



void

icmn_err(register int level, char *fmt, va_list ap)

xfs_fs_vcmn_err(

	int			level,

	struct xfs_mount	*mp,

	char			*fmt,

	va_list			ap)

{

	ulong	flags;

	int	len;

	unsigned long		flags;

	int			len = 0;



	level &= XFS_ERR_MASK;

	if (level > XFS_MAX_ERR_LEVEL)

		level = XFS_MAX_ERR_LEVEL;



	spin_lock_irqsave(&xfs_err_lock,flags);

	len = vsnprintf(message, sizeof(message), fmt, ap);



	if (mp) {

		len = sprintf(message, "Filesystem \"%s\": ", mp->m_fsname);



		/*

		 * Skip the printk if we can't print anything useful

		 * due to an over-long device name.

		 */

		if (len >= sizeof(message))

			goto out;

	}



	len = vsnprintf(message + len, sizeof(message) - len, fmt, ap);

	if (len >= sizeof(message))

		len = sizeof(message) - 1;

	if (message[len-1] == '\n')

		message[len-1] = 0;



	printk("%s%s\n", err_level[level], message);

 out:

	spin_unlock_irqrestore(&xfs_err_lock,flags);



	BUG_ON(level == CE_PANIC);

}

fs/xfs/support/debug.h

+0 −2
Original line number Diff line number Diff line
@@ -27,8 +27,6 @@ 
#define CE_ALERT        1               /* alert        */

#define CE_PANIC        0               /* panic        */



extern void icmn_err(int, char *, va_list)

	__attribute__ ((format (printf, 2, 0)));

extern void cmn_err(int, char *, ...)

	__attribute__ ((format (printf, 2, 3)));

extern void assfail(char *expr, char *f, int l);

fs/xfs/xfs_error.c

+0 −15
Original line number Diff line number Diff line
@@ -153,21 +153,6 @@ xfs_errortag_clearall(xfs_mount_t *mp, int loud) 
}

#endif /* DEBUG */



static void

xfs_fs_vcmn_err(int level, xfs_mount_t *mp, char *fmt, va_list ap)

{

	if (mp != NULL) {

		char	*newfmt;

		int	len = 16 + mp->m_fsname_len + strlen(fmt);



		newfmt = kmem_alloc(len, KM_SLEEP);

		sprintf(newfmt, "Filesystem \"%s\": %s", mp->m_fsname, fmt);

		icmn_err(level, newfmt, ap);

		kmem_free(newfmt);

	} else {

		icmn_err(level, fmt, ap);

	}

}



void

xfs_fs_cmn_err(int level, xfs_mount_t *mp, char *fmt, ...)

fs/xfs/xfs_error.h

+8 −4
Original line number Diff line number Diff line
@@ -159,11 +159,15 @@ extern int xfs_errortag_clearall(xfs_mount_t *mp, int loud); 
#define		XFS_PTAG_FSBLOCK_ZERO		0x00000080



struct xfs_mount;

/* PRINTFLIKE4 */



extern void xfs_fs_vcmn_err(int level, struct xfs_mount *mp,

		char *fmt, va_list ap)

	__attribute__ ((format (printf, 3, 0)));

extern void xfs_cmn_err(int panic_tag, int level, struct xfs_mount *mp,

			char *fmt, ...);

/* PRINTFLIKE3 */

extern void xfs_fs_cmn_err(int level, struct xfs_mount *mp, char *fmt, ...);

			char *fmt, ...)

	__attribute__ ((format (printf, 4, 5)));

extern void xfs_fs_cmn_err(int level, struct xfs_mount *mp, char *fmt, ...)

	__attribute__ ((format (printf, 3, 4)));



extern void xfs_hex_dump(void *p, int length);