Jiri Slaby 999898355e ipc: msg, make msgrcv work with LONG_MIN ... When LONG_MIN is passed to msgrcv, one would expect to recieve any message. But convert_mode does *msgtyp = -*msgtyp and -LONG_MIN is undefined. In particular, with my gcc -LONG_MIN produces -LONG_MIN again. So handle this case properly by assigning LONG_MAX to *msgtyp if LONG_MIN was specified as msgtyp to msgrcv. This code: long msg[] = { 100, 200 }; int m = msgget(IPC_PRIVATE, IPC_CREAT | 0644); msgsnd(m, &msg, sizeof(msg), 0); msgrcv(m, &msg, sizeof(msg), LONG_MIN, 0); produces currently nothing: msgget(IPC_PRIVATE, IPC_CREAT|0644) = 65538 msgsnd(65538, {100, "\310\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16, 0) = 0 msgrcv(65538, ... Except a UBSAN warning: UBSAN: Undefined behaviour in ipc/msg.c:745:13 negation of -9223372036854775808 cannot be represented in type 'long int': With the patch, I see what I expect: msgget(IPC_PRIVATE, IPC_CREAT|0644) = 0 msgsnd(0, {100, "\310\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16, 0) = 0 msgrcv(0, {100, "\310\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16, -9223372036854775808, 0) = 16 Link: http://lkml.kernel.org/r/20161024082633.10148-1-jslaby@suse.cz Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2016-12-14 16:04:08 -08:00
..
compat_mq.c
compat.c
ipc_sysctl.c
Makefile
mq_sysctl.c
mqueue.c	sched/wake_q: Rename WAKE_Q to DEFINE_WAKE_Q	2016-11-21 10:29:01 +01:00
msg.c	ipc: msg, make msgrcv work with LONG_MIN	2016-12-14 16:04:08 -08:00
msgutil.c	ipc: account for kmem usage on mqueue and msg	2016-10-27 18:43:43 -07:00
namespace.c	Merge branch 'nsfs-ioctls' into HEAD	2016-09-22 20:00:36 -05:00
sem.c	ipc/sem.c: add cond_resched in exit_sme	2016-10-11 15:06:33 -07:00
shm.c	shmem: make shmem_inode_info::lock irq-safe	2016-07-26 16:19:19 -07:00
syscall.c
util.c
util.h