The patch titled Subject: drivers/char/random.c: fix boot id uniqueness race has been removed from the -mm tree. Its filename was drivers-char-randomc-fix-boot-id-uniqueness-race.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Subject: drivers/char/random.c: fix boot id uniqueness race /proc/sys/kernel/random/boot_id can be read concurrently by userspace processes. If two (or more) user-space processes concurrently read boot_id when sysctl_bootid is not yet assigned, a race can occur making boot_id differ between the reads. Because the whole point of the boot id is to be unique across a kernel execution, fix this by protecting this operation with a spinlock. Given that this operation is not frequently used, hitting the spinlock on each call should not be an issue. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Cc: "Theodore Ts'o" <tytso@xxxxxxx> Cc: Matt Mackall <mpm@xxxxxxxxxxx> Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx> Cc: Greg Kroah-Hartman <greg@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/char/random.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff -puN drivers/char/random.c~drivers-char-randomc-fix-boot-id-uniqueness-race drivers/char/random.c --- a/drivers/char/random.c~drivers-char-randomc-fix-boot-id-uniqueness-race +++ a/drivers/char/random.c @@ -1260,10 +1260,15 @@ static int proc_do_uuid(ctl_table *table uuid = table->data; if (!uuid) { uuid = tmp_uuid; - uuid[8] = 0; - } - if (uuid[8] == 0) generate_random_uuid(uuid); + } else { + static DEFINE_SPINLOCK(bootid_spinlock); + + spin_lock(&bootid_spinlock); + if (!uuid[8]) + generate_random_uuid(uuid); + spin_unlock(&bootid_spinlock); + } sprintf(buf, "%pU", uuid); _ Patches currently in -mm which might be from mathieu.desnoyers@xxxxxxxxxxxx are -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html