kernel/linux.git/drivers/hv/hv_util.c, branch linux-7.1.y

Drivers: hv: use kmalloc_array() instead of kmalloc()

2025-12-05T23:16:49+00:00

Replace kmalloc() with kmalloc_array() to prevent potential overflow, as recommended in Documentation/process/deprecated.rst. Signed-off-by: Gongwei Li Signed-off-by: Wei Liu

Drivers: hv: util: Avoid accessing a ringbuffer not initialized yet

2024-12-09T18:44:15+00:00

If the KVP (or VSS) daemon starts before the VMBus channel's ringbuffer is fully initialized, we can hit the panic below: hv_utils: Registering HyperV Utility Driver hv_vmbus: registering driver hv_utils ... BUG: kernel NULL pointer dereference, address: 0000000000000000 CPU: 44 UID: 0 PID: 2552 Comm: hv_kvp_daemon Tainted: G E 6.11.0-rc3+ #1 RIP: 0010:hv_pkt_iter_first+0x12/0xd0 Call Trace: ... vmbus_recvpacket hv_kvp_onchannelcallback vmbus_on_event tasklet_action_common tasklet_action handle_softirqs irq_exit_rcu sysvec_hyperv_stimer0 asm_sysvec_hyperv_stimer0 ... kvp_register_done hvt_op_read vfs_read ksys_read __x64_sys_read This can happen because the KVP/VSS channel callback can be invoked even before the channel is fully opened: 1) as soon as hv_kvp_init() -> hvutil_transport_init() creates /dev/vmbus/hv_kvp, the kvp daemon can open the device file immediately and register itself to the driver by writing a message KVP_OP_REGISTER1 to the file (which is handled by kvp_on_msg() ->kvp_handle_handshake()) and reading the file for the driver's response, which is handled by hvt_op_read(), which calls hvt->on_read(), i.e. kvp_register_done(). 2) the problem with kvp_register_done() is that it can cause the channel callback to be called even before the channel is fully opened, and when the channel callback is starting to run, util_probe()-> vmbus_open() may have not initialized the ringbuffer yet, so the callback can hit the panic of NULL pointer dereference. To reproduce the panic consistently, we can add a "ssleep(10)" for KVP in __vmbus_open(), just before the first hv_ringbuffer_init(), and then we unload and reload the driver hv_utils, and run the daemon manually within the 10 seconds. Fix the panic by reordering the steps in util_probe() so the char dev entry used by the KVP or VSS daemon is not created until after vmbus_open() has completed. This reordering prevents the race condition from happening. Reported-by: Dexuan Cui Fixes: e0fa3e5e7df6 ("Drivers: hv: utils: fix a race on userspace daemons registration") Cc: stable@vger.kernel.org Signed-off-by: Michael Kelley Acked-by: Wei Liu Link: https://lore.kernel.org/r/20241106154247.2271-3-mhklinux@outlook.com Signed-off-by: Wei Liu Message-ID: <20241106154247.2271-3-mhklinux@outlook.com>

Drivers: hv: util: Don't force error code to ENODEV in util_probe()

2024-12-09T18:44:14+00:00

If the util_init function call in util_probe() returns an error code, util_probe() always return ENODEV, and the error code from the util_init function is lost. The error message output in the caller, vmbus_probe(), doesn't show the real error code. Fix this by just returning the error code from the util_init function. There doesn't seem to be a reason to force ENODEV, as other errors such as ENOMEM can already be returned from util_probe(). And the code in call_driver_probe() implies that ENODEV should mean that a matching driver wasn't found, which is not the case here. Suggested-by: Dexuan Cui Signed-off-by: Michael Kelley Acked-by: Wei Liu Link: https://lore.kernel.org/r/20241106154247.2271-2-mhklinux@outlook.com Signed-off-by: Wei Liu Message-ID: <20241106154247.2271-2-mhklinux@outlook.com>

Drivers: hv: Remove fcopy driver

2024-04-11T12:55:53+00:00

As the new fcopy driver using uio is introduced, remove obsolete driver and application. Signed-off-by: Saurabh Sengar Reviewed-by: Long Li Link: https://lore.kernel.org/r/1711788723-8593-7-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Greg Kroah-Hartman

hv_utils: Allow implicit ICTIMESYNCFLAG_SYNC

2024-03-01T08:19:06+00:00

Hyper-V hosts can omit the _SYNC flag to due a bug on resume from modern suspend. In such a case, the guest may fail to update its time-of-day to account for the period when it was suspended, and could proceed with a significantly wrong time-of-day. In such a case when the guest is significantly behind, fix it by treating a _SAMPLE the same as if _SYNC was received so that the guest time-of-day is updated. This is hidden behind param hv_utils.timesync_implicit. Signed-off-by: Peter Martincic Acked-by: Boqun Feng Link: https://lore.kernel.org/r/20231127213524.52783-1-pmartincic@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <20231127213524.52783-1-pmartincic@linux.microsoft.com>

Drivers: hv: Make remove callback of hyperv driver void returned

2023-01-17T13:41:27+00:00

Since commit fc7a6209d571 ("bus: Make remove callback return void") forces bus_type::remove be void-returned, it doesn't make much sense for any bus based driver implementing remove callbalk to return non-void to its caller. As such, change the remove function for Hyper-V VMBus based drivers to return void. Signed-off-by: Dawei Li Link: https://lore.kernel.org/r/TYCP286MB2323A93C55526E4DF239D3ACCAFA9@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM Signed-off-by: Wei Liu

drivers: convert unsupported .adjfreq to .adjfine

2022-10-31T11:14:16+00:00

A few PTP drivers implement a .adjfreq handler which indicates the operation is not supported. Convert all of these to .adjfine. Signed-off-by: Jacob Keller Acked-by: Richard Cochran Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Wei Liu Cc: Dexuan Cui Cc: Vivek Thampi Signed-off-by: David S. Miller

drivers: hv: Decouple Hyper-V clock/timer code from VMbus drivers

2021-07-19T09:24:28+00:00

Hyper-V clock/timer code in hyperv_timer.c is mostly independent from other VMbus drivers, but building for ARM64 without hyperv_timer.c shows some remaining entanglements. A default implementation of hv_read_reference_counter can just read a Hyper-V synthetic register and be independent of hyperv_timer.c, so move this code out and into hv_common.c. Then it can be used by the timesync driver even if hyperv_timer.c isn't built on a particular architecture. If hyperv_timer.c *is* built, it can override with a faster implementation. Also provide stubs for stimer functions called by the VMbus driver when hyperv_timer.c isn't built. No functional changes. Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1626220906-22629-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

hv_utils: Fix passing zero to 'PTR_ERR' warning

2021-05-18T10:50:46+00:00

Sparse warn this: drivers/hv/hv_util.c:753 hv_timesync_init() warn: passing zero to 'PTR_ERR' Use PTR_ERR_OR_ZERO instead of PTR_ERR to fix this. Signed-off-by: YueHaibing Link: https://lore.kernel.org/r/20210514070116.16800-1-yuehaibing@huawei.com [ wei: change %ld to %d ] Signed-off-by: Wei Liu

hv_utils: Fix spelling mistake "Hearbeat" -> "Heartbeat"

2021-02-11T08:47:05+00:00

There is a spelling mistake in an error message. Fix it. Signed-off-by: Colin Ian King Link: https://lore.kernel.org/r/20210127233136.623465-1-colin.king@canonical.com Signed-off-by: Wei Liu