CVE-2026-46118

In the Linux kernel, the following vulnerability has been resolved:

pseries/papr-hvpipe: Fix null ptr deref in papr_hvpipe_dev_create_handle()

commit 6d3789d347a7 ("papr-hvpipe: convert papr_hvpipe_dev_create_handle() to FD_PREPARE()"),

changed the create handle to FD_PREPARE(), but it caused kernel

null-ptr-deref because after call to retain_and_null_ptr(src_info),

src_info is re-used for adding it to the global list.

Getting the following kernel panic in papr_hvpipe_dev_create_handle()

when trying to add src_info to the list.

Kernel attempted to write user page (0) - exploit attempt? (uid: 0)

BUG: Kernel NULL pointer dereference on write at 0x00000000

Faulting instruction address: 0xc0000000001b44a0

Oops: Kernel access of bad area, sig: 11 [#1]

...

Call Trace:

papr_hvpipe_dev_ioctl+0x1f4/0x48c (unreliable)

sys_ioctl+0x528/0x1064

system_call_exception+0x128/0x360

system_call_vectored_common+0x15c/0x2ec

Now, the error handling with FD_PREPARE's file cleanup and __free(kfree) auto

cleanup is getting too convoluted. This is mainly because we need to

ensure only 1 user get the srcID handle. To simplify this, we allocate

prepare the src_info in the beginning and add it to the global list

under a spinlock after checking that no duplicates exist.

This simplify the error handling where if the FD_ADD fails, we can

simply remove the src_info from the list and consume any pending msg in

hvpipe to be cleared, after src_info became visible in the global list.