This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.
As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
In the function bcm_vk_read(), the pointer entry is checked, indicating
that it can be NULL. If entry is NULL and rc is set to -EMSGSIZE, the
following code may cause null-pointer dereferences:
struct vk_msg_blk tmp_msg = entry->to_h_msg[0];
set_msg_id(&tmp_msg, entry->usr_msg_id);
tmp_msg.size = entry->to_h_blks - 1;
To prevent these possible null-pointer dereferences, copy to_h_msg,
usr_msg_id, and to_h_blks from iter into temporary variables, and return
these temporary variables to the application instead of accessing them
through a potentially NULL entry.
Signed-off-by: Tuo Li <islituo@gmail.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Link: https://patch.msgid.link/20251211063637.3987937-1-islituo@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As &vk->ctx_lock is acquired by timer bcm_vk_hb_poll() under softirq
context, other process context code should disable irq or bottom-half
before acquire the same lock, otherwise deadlock could happen if the
timer preempt the execution while the lock is held in process context
on the same CPU.
Possible deadlock scenario
bcm_vk_open()
-> bcm_vk_get_ctx()
-> spin_lock(&vk->ctx_lock)
<timer iterrupt>
-> bcm_vk_hb_poll()
-> bcm_vk_blk_drv_access()
-> spin_lock_irqsave(&vk->ctx_lock, flags) (deadlock here)
This flaw was found using an experimental static analysis tool we are
developing for irq-related deadlock, which reported the following
warning when analyzing the linux kernel 6.4-rc7 release.
[Deadlock]: &vk->ctx_lock
[Interrupt]: bcm_vk_hb_poll
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_msg.c:176
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_dev.c:512
[Locking Unit]: bcm_vk_ioctl
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_dev.c:1181
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_dev.c:512
[Deadlock]: &vk->ctx_lock
[Interrupt]: bcm_vk_hb_poll
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_msg.c:176
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_dev.c:512
[Locking Unit]: bcm_vk_ioctl
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_dev.c:1169
[Deadlock]: &vk->ctx_lock
[Interrupt]: bcm_vk_hb_poll
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_msg.c:176
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_dev.c:512
[Locking Unit]: bcm_vk_open
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_msg.c:216
[Deadlock]: &vk->ctx_lock
[Interrupt]: bcm_vk_hb_poll
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_msg.c:176
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_dev.c:512
[Locking Unit]: bcm_vk_release
-->/root/linux/drivers/misc/bcm-vk/bcm_vk_msg.c:306
As suggested by Arnd, the tentative patch fix the potential deadlocks
by replacing the timer with delay workqueue. x86_64 allyesconfig using
GCC shows no new warning. Note that no runtime testing was performed
due to no device on hand.
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Tested-by: Desmond Yan <desmond.branden@broadcom.com>
Tested-by: Desmond Yan <desmond.yan@broadcom.com>
Link: https://lore.kernel.org/r/20230629182941.13045-1-dg573847474@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
