From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- net/mac802154/driver-ops.h | 354 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 354 insertions(+) create mode 100644 net/mac802154/driver-ops.h (limited to 'net/mac802154/driver-ops.h') diff --git a/net/mac802154/driver-ops.h b/net/mac802154/driver-ops.h new file mode 100644 index 000000000..a7af3f0dd --- /dev/null +++ b/net/mac802154/driver-ops.h @@ -0,0 +1,354 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __MAC802154_DRIVER_OPS +#define __MAC802154_DRIVER_OPS + +#include +#include + +#include + +#include "ieee802154_i.h" +#include "trace.h" + +static inline int +drv_xmit_async(struct ieee802154_local *local, struct sk_buff *skb) +{ + return local->ops->xmit_async(&local->hw, skb); +} + +static inline int +drv_xmit_sync(struct ieee802154_local *local, struct sk_buff *skb) +{ + might_sleep(); + + return local->ops->xmit_sync(&local->hw, skb); +} + +static inline int drv_set_pan_id(struct ieee802154_local *local, __le16 pan_id) +{ + struct ieee802154_hw_addr_filt filt; + int ret; + + might_sleep(); + + if (!local->ops->set_hw_addr_filt) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + filt.pan_id = pan_id; + + trace_802154_drv_set_pan_id(local, pan_id); + ret = local->ops->set_hw_addr_filt(&local->hw, &filt, + IEEE802154_AFILT_PANID_CHANGED); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int +drv_set_extended_addr(struct ieee802154_local *local, __le64 extended_addr) +{ + struct ieee802154_hw_addr_filt filt; + int ret; + + might_sleep(); + + if (!local->ops->set_hw_addr_filt) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + filt.ieee_addr = extended_addr; + + trace_802154_drv_set_extended_addr(local, extended_addr); + ret = local->ops->set_hw_addr_filt(&local->hw, &filt, + IEEE802154_AFILT_IEEEADDR_CHANGED); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int +drv_set_short_addr(struct ieee802154_local *local, __le16 short_addr) +{ + struct ieee802154_hw_addr_filt filt; + int ret; + + might_sleep(); + + if (!local->ops->set_hw_addr_filt) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + filt.short_addr = short_addr; + + trace_802154_drv_set_short_addr(local, short_addr); + ret = local->ops->set_hw_addr_filt(&local->hw, &filt, + IEEE802154_AFILT_SADDR_CHANGED); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int +drv_set_pan_coord(struct ieee802154_local *local, bool is_coord) +{ + struct ieee802154_hw_addr_filt filt; + int ret; + + might_sleep(); + + if (!local->ops->set_hw_addr_filt) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + filt.pan_coord = is_coord; + + trace_802154_drv_set_pan_coord(local, is_coord); + ret = local->ops->set_hw_addr_filt(&local->hw, &filt, + IEEE802154_AFILT_PANC_CHANGED); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int +drv_set_promiscuous_mode(struct ieee802154_local *local, bool on) +{ + int ret; + + might_sleep(); + + if (!local->ops->set_promiscuous_mode) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + trace_802154_drv_set_promiscuous_mode(local, on); + ret = local->ops->set_promiscuous_mode(&local->hw, on); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int drv_start(struct ieee802154_local *local, + enum ieee802154_filtering_level level, + const struct ieee802154_hw_addr_filt *addr_filt) +{ + int ret; + + might_sleep(); + + /* setup receive mode parameters e.g. address mode */ + if (local->hw.flags & IEEE802154_HW_AFILT) { + ret = drv_set_pan_id(local, addr_filt->pan_id); + if (ret < 0) + return ret; + + ret = drv_set_short_addr(local, addr_filt->short_addr); + if (ret < 0) + return ret; + + ret = drv_set_extended_addr(local, addr_filt->ieee_addr); + if (ret < 0) + return ret; + } + + switch (level) { + case IEEE802154_FILTERING_NONE: + fallthrough; + case IEEE802154_FILTERING_1_FCS: + fallthrough; + case IEEE802154_FILTERING_2_PROMISCUOUS: + /* TODO: Requires a different receive mode setup e.g. + * at86rf233 hardware. + */ + fallthrough; + case IEEE802154_FILTERING_3_SCAN: + if (local->hw.flags & IEEE802154_HW_PROMISCUOUS) { + ret = drv_set_promiscuous_mode(local, true); + if (ret < 0) + return ret; + } else { + return -EOPNOTSUPP; + } + + /* In practice other filtering levels can be requested, but as + * for now most hardware/drivers only support + * IEEE802154_FILTERING_NONE, we fallback to this actual + * filtering level in hardware and make our own additional + * filtering in mac802154 receive path. + * + * TODO: Move this logic to the device drivers as hardware may + * support more higher level filters. Hardware may also require + * a different order how register are set, which could currently + * be buggy, so all received parameters need to be moved to the + * start() callback and let the driver go into the mode before + * it will turn on receive handling. + */ + local->phy->filtering = IEEE802154_FILTERING_NONE; + break; + case IEEE802154_FILTERING_4_FRAME_FIELDS: + /* Do not error out if IEEE802154_HW_PROMISCUOUS because we + * expect the hardware to operate at the level + * IEEE802154_FILTERING_4_FRAME_FIELDS anyway. + */ + if (local->hw.flags & IEEE802154_HW_PROMISCUOUS) { + ret = drv_set_promiscuous_mode(local, false); + if (ret < 0) + return ret; + } + + local->phy->filtering = IEEE802154_FILTERING_4_FRAME_FIELDS; + break; + default: + WARN_ON(1); + return -EINVAL; + } + + trace_802154_drv_start(local); + local->started = true; + smp_mb(); + ret = local->ops->start(&local->hw); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline void drv_stop(struct ieee802154_local *local) +{ + might_sleep(); + + trace_802154_drv_stop(local); + local->ops->stop(&local->hw); + trace_802154_drv_return_void(local); + + /* sync away all work on the tasklet before clearing started */ + tasklet_disable(&local->tasklet); + tasklet_enable(&local->tasklet); + + barrier(); + + local->started = false; +} + +static inline int +drv_set_channel(struct ieee802154_local *local, u8 page, u8 channel) +{ + int ret; + + might_sleep(); + + trace_802154_drv_set_channel(local, page, channel); + ret = local->ops->set_channel(&local->hw, page, channel); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int drv_set_tx_power(struct ieee802154_local *local, s32 mbm) +{ + int ret; + + might_sleep(); + + if (!local->ops->set_txpower) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + trace_802154_drv_set_tx_power(local, mbm); + ret = local->ops->set_txpower(&local->hw, mbm); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int drv_set_cca_mode(struct ieee802154_local *local, + const struct wpan_phy_cca *cca) +{ + int ret; + + might_sleep(); + + if (!local->ops->set_cca_mode) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + trace_802154_drv_set_cca_mode(local, cca); + ret = local->ops->set_cca_mode(&local->hw, cca); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int drv_set_lbt_mode(struct ieee802154_local *local, bool mode) +{ + int ret; + + might_sleep(); + + if (!local->ops->set_lbt) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + trace_802154_drv_set_lbt_mode(local, mode); + ret = local->ops->set_lbt(&local->hw, mode); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int +drv_set_cca_ed_level(struct ieee802154_local *local, s32 mbm) +{ + int ret; + + might_sleep(); + + if (!local->ops->set_cca_ed_level) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + trace_802154_drv_set_cca_ed_level(local, mbm); + ret = local->ops->set_cca_ed_level(&local->hw, mbm); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int +drv_set_csma_params(struct ieee802154_local *local, u8 min_be, u8 max_be, + u8 max_csma_backoffs) +{ + int ret; + + might_sleep(); + + if (!local->ops->set_csma_params) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + trace_802154_drv_set_csma_params(local, min_be, max_be, + max_csma_backoffs); + ret = local->ops->set_csma_params(&local->hw, min_be, max_be, + max_csma_backoffs); + trace_802154_drv_return_int(local, ret); + return ret; +} + +static inline int +drv_set_max_frame_retries(struct ieee802154_local *local, s8 max_frame_retries) +{ + int ret; + + might_sleep(); + + if (!local->ops->set_frame_retries) { + WARN_ON(1); + return -EOPNOTSUPP; + } + + trace_802154_drv_set_max_frame_retries(local, max_frame_retries); + ret = local->ops->set_frame_retries(&local->hw, max_frame_retries); + trace_802154_drv_return_int(local, ret); + return ret; +} + +#endif /* __MAC802154_DRIVER_OPS */ -- cgit v1.3.1