kernel/drivers/usb/class/cdc-wdm.c, branch master

usb: class: cdc-wdm: fix reordering issue in read code path

2026-03-11T15:18:31Z

Quoting the bug report: Due to compiler optimization or CPU out-of-order execution, the desc->length update can be reordered before the memmove. If this happens, wdm_read() can see the new length and call copy_to_user() on uninitialized memory. This also violates LKMM data race rules [1]. Fix it by using WRITE_ONCE and memory barriers. Fixes: afba937e540c9 ("USB: CDC WDM driver") Cc: stable Signed-off-by: Oliver Neukum Closes: https://lore.kernel.org/linux-usb/CALbr=LbrUZn_cfp7CfR-7Z5wDTHF96qeuM=3fO2m-q4cDrnC4A@mail.gmail.com/ Reported-by: Gui-Dong Han Reviewed-by: Gui-Dong Han Link: https://patch.msgid.link/20260304130116.1721682-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51Z

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28Z

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

Merge 6.15-rc4 into usb-next

2025-04-28T08:32:58Z

We need the USB fixes in here as well, and this resolves the following merge conflicts that were reported in linux-next: drivers/usb/chipidea/ci_hdrc_imx.c drivers/usb/host/xhci.h Reported-by: Stephen Rothwell Signed-off-by: Greg Kroah-Hartman

USB: wdm: add annotation

2025-04-11T14:27:34Z

This is not understandable without a comment on endianness Fixes: afba937e540c9 ("USB: CDC WDM driver") Cc: stable Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20250401084749.175246-5-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman

USB: wdm: wdm_wwan_port_tx_complete mutex in atomic context

2025-04-11T14:27:32Z

wdm_wwan_port_tx_complete is called from a completion handler with irqs disabled and possible in IRQ context usb_autopm_put_interface can take a mutex. Hence usb_autopm_put_interface_async must be used. Fixes: cac6fb015f71 ("usb: class: cdc-wdm: WWAN framework integration") Cc: stable Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20250401084749.175246-4-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman

USB: wdm: close race between wdm_open and wdm_wwan_port_stop

2025-04-11T14:27:28Z

Clearing WDM_WWAN_IN_USE must be the last action or we can open a chardev whose URBs are still poisoned Fixes: cac6fb015f71 ("usb: class: cdc-wdm: WWAN framework integration") Cc: stable Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20250401084749.175246-3-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman

USB: wdm: handle IO errors in wdm_wwan_port_start

2025-04-11T14:27:25Z

In case submitting the URB fails we must undo what we've done so far. Fixes: cac6fb015f71 ("usb: class: cdc-wdm: WWAN framework integration") Cc: stable Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20250401084749.175246-2-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman

usb: cdc-wdm: avoid setting WDM_READ for ZLP-s

2025-04-11T14:08:33Z

Don't set WDM_READ flag in wdm_in_callback() for ZLP-s, otherwise when userspace tries to poll for available data, it might - incorrectly - believe there is something available, and when it tries to non-blocking read it, it might get stuck in the read loop. For example this is what glib does for non-blocking read (briefly): 1. poll() 2. if poll returns with non-zero, starts a read data loop: a. loop on poll() (EINTR disabled) b. if revents was set, reads data I. if read returns with EINTR or EAGAIN, goto 2.a. II. otherwise return with data So if ZLP sets WDM_READ (#1), we expect data, and try to read it (#2). But as that was a ZLP, and we are doing non-blocking read, wdm_read() returns with EAGAIN (#2.b.I), so loop again, and try to read again (#2.a.). With glib, we might stuck in this loop forever, as EINTR is disabled (#2.a). Signed-off-by: Robert Hodaszi Acked-by: Oliver Neukum Link: https://lore.kernel.org/r/20250403144004.3889125-1-robert.hodaszi@digi.com Signed-off-by: Greg Kroah-Hartman

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23Z

asm/unaligned.h is always an include of asm-generic/unaligned.h; might as well move that thing to linux/unaligned.h and include that - there's nothing arch-specific in that header. auto-generated by the following: for i in `git grep -l -w asm/unaligned.h`; do sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i done for i in `git grep -l -w asm-generic/unaligned.h`; do sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i done git mv include/asm-generic/unaligned.h include/linux/unaligned.h git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h