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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /mm/kfence/report.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'mm/kfence/report.c')
-rw-r--r--mm/kfence/report.c327
1 files changed, 327 insertions, 0 deletions
diff --git a/mm/kfence/report.c b/mm/kfence/report.c
new file mode 100644
index 000000000..60205f125
--- /dev/null
+++ b/mm/kfence/report.c
@@ -0,0 +1,327 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KFENCE reporting.
+ *
+ * Copyright (C) 2020, Google LLC.
+ */
+
+#include <linux/stdarg.h>
+
+#include <linux/kernel.h>
+#include <linux/lockdep.h>
+#include <linux/math.h>
+#include <linux/printk.h>
+#include <linux/sched/debug.h>
+#include <linux/seq_file.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+#include <trace/events/error_report.h>
+
+#include <asm/kfence.h>
+
+#include "kfence.h"
+
+/* May be overridden by <asm/kfence.h>. */
+#ifndef ARCH_FUNC_PREFIX
+#define ARCH_FUNC_PREFIX ""
+#endif
+
+extern bool no_hash_pointers;
+
+/* Helper function to either print to a seq_file or to console. */
+__printf(2, 3)
+static void seq_con_printf(struct seq_file *seq, const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ if (seq)
+ seq_vprintf(seq, fmt, args);
+ else
+ vprintk(fmt, args);
+ va_end(args);
+}
+
+/*
+ * Get the number of stack entries to skip to get out of MM internals. @type is
+ * optional, and if set to NULL, assumes an allocation or free stack.
+ */
+static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries,
+ const enum kfence_error_type *type)
+{
+ char buf[64];
+ int skipnr, fallback = 0;
+
+ if (type) {
+ /* Depending on error type, find different stack entries. */
+ switch (*type) {
+ case KFENCE_ERROR_UAF:
+ case KFENCE_ERROR_OOB:
+ case KFENCE_ERROR_INVALID:
+ /*
+ * kfence_handle_page_fault() may be called with pt_regs
+ * set to NULL; in that case we'll simply show the full
+ * stack trace.
+ */
+ return 0;
+ case KFENCE_ERROR_CORRUPTION:
+ case KFENCE_ERROR_INVALID_FREE:
+ break;
+ }
+ }
+
+ for (skipnr = 0; skipnr < num_entries; skipnr++) {
+ int len = scnprintf(buf, sizeof(buf), "%ps", (void *)stack_entries[skipnr]);
+
+ if (str_has_prefix(buf, ARCH_FUNC_PREFIX "kfence_") ||
+ str_has_prefix(buf, ARCH_FUNC_PREFIX "__kfence_") ||
+ str_has_prefix(buf, ARCH_FUNC_PREFIX "__kmem_cache_free") ||
+ !strncmp(buf, ARCH_FUNC_PREFIX "__slab_free", len)) {
+ /*
+ * In case of tail calls from any of the below to any of
+ * the above, optimized by the compiler such that the
+ * stack trace would omit the initial entry point below.
+ */
+ fallback = skipnr + 1;
+ }
+
+ /*
+ * The below list should only include the initial entry points
+ * into the slab allocators. Includes the *_bulk() variants by
+ * checking prefixes.
+ */
+ if (str_has_prefix(buf, ARCH_FUNC_PREFIX "kfree") ||
+ str_has_prefix(buf, ARCH_FUNC_PREFIX "kmem_cache_free") ||
+ str_has_prefix(buf, ARCH_FUNC_PREFIX "__kmalloc") ||
+ str_has_prefix(buf, ARCH_FUNC_PREFIX "kmem_cache_alloc"))
+ goto found;
+ }
+ if (fallback < num_entries)
+ return fallback;
+found:
+ skipnr++;
+ return skipnr < num_entries ? skipnr : 0;
+}
+
+static void kfence_print_stack(struct seq_file *seq, const struct kfence_metadata *meta,
+ bool show_alloc)
+{
+ const struct kfence_track *track = show_alloc ? &meta->alloc_track : &meta->free_track;
+ u64 ts_sec = track->ts_nsec;
+ unsigned long rem_nsec = do_div(ts_sec, NSEC_PER_SEC);
+
+ /* Timestamp matches printk timestamp format. */
+ seq_con_printf(seq, "%s by task %d on cpu %d at %lu.%06lus:\n",
+ show_alloc ? "allocated" : "freed", track->pid,
+ track->cpu, (unsigned long)ts_sec, rem_nsec / 1000);
+
+ if (track->num_stack_entries) {
+ /* Skip allocation/free internals stack. */
+ int i = get_stack_skipnr(track->stack_entries, track->num_stack_entries, NULL);
+
+ /* stack_trace_seq_print() does not exist; open code our own. */
+ for (; i < track->num_stack_entries; i++)
+ seq_con_printf(seq, " %pS\n", (void *)track->stack_entries[i]);
+ } else {
+ seq_con_printf(seq, " no %s stack\n", show_alloc ? "allocation" : "deallocation");
+ }
+}
+
+void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta)
+{
+ const int size = abs(meta->size);
+ const unsigned long start = meta->addr;
+ const struct kmem_cache *const cache = meta->cache;
+
+ lockdep_assert_held(&meta->lock);
+
+ if (meta->state == KFENCE_OBJECT_UNUSED) {
+ seq_con_printf(seq, "kfence-#%td unused\n", meta - kfence_metadata);
+ return;
+ }
+
+ seq_con_printf(seq, "kfence-#%td: 0x%p-0x%p, size=%d, cache=%s\n\n",
+ meta - kfence_metadata, (void *)start, (void *)(start + size - 1),
+ size, (cache && cache->name) ? cache->name : "<destroyed>");
+
+ kfence_print_stack(seq, meta, true);
+
+ if (meta->state == KFENCE_OBJECT_FREED) {
+ seq_con_printf(seq, "\n");
+ kfence_print_stack(seq, meta, false);
+ }
+}
+
+/*
+ * Show bytes at @addr that are different from the expected canary values, up to
+ * @max_bytes.
+ */
+static void print_diff_canary(unsigned long address, size_t bytes_to_show,
+ const struct kfence_metadata *meta)
+{
+ const unsigned long show_until_addr = address + bytes_to_show;
+ const u8 *cur, *end;
+
+ /* Do not show contents of object nor read into following guard page. */
+ end = (const u8 *)(address < meta->addr ? min(show_until_addr, meta->addr)
+ : min(show_until_addr, PAGE_ALIGN(address)));
+
+ pr_cont("[");
+ for (cur = (const u8 *)address; cur < end; cur++) {
+ if (*cur == KFENCE_CANARY_PATTERN(cur))
+ pr_cont(" .");
+ else if (no_hash_pointers)
+ pr_cont(" 0x%02x", *cur);
+ else /* Do not leak kernel memory in non-debug builds. */
+ pr_cont(" !");
+ }
+ pr_cont(" ]");
+}
+
+static const char *get_access_type(bool is_write)
+{
+ return is_write ? "write" : "read";
+}
+
+void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs,
+ const struct kfence_metadata *meta, enum kfence_error_type type)
+{
+ unsigned long stack_entries[KFENCE_STACK_DEPTH] = { 0 };
+ const ptrdiff_t object_index = meta ? meta - kfence_metadata : -1;
+ int num_stack_entries;
+ int skipnr = 0;
+
+ if (regs) {
+ num_stack_entries = stack_trace_save_regs(regs, stack_entries, KFENCE_STACK_DEPTH, 0);
+ } else {
+ num_stack_entries = stack_trace_save(stack_entries, KFENCE_STACK_DEPTH, 1);
+ skipnr = get_stack_skipnr(stack_entries, num_stack_entries, &type);
+ }
+
+ /* Require non-NULL meta, except if KFENCE_ERROR_INVALID. */
+ if (WARN_ON(type != KFENCE_ERROR_INVALID && !meta))
+ return;
+
+ if (meta)
+ lockdep_assert_held(&meta->lock);
+ /*
+ * Because we may generate reports in printk-unfriendly parts of the
+ * kernel, such as scheduler code, the use of printk() could deadlock.
+ * Until such time that all printing code here is safe in all parts of
+ * the kernel, accept the risk, and just get our message out (given the
+ * system might already behave unpredictably due to the memory error).
+ * As such, also disable lockdep to hide warnings, and avoid disabling
+ * lockdep for the rest of the kernel.
+ */
+ lockdep_off();
+
+ pr_err("==================================================================\n");
+ /* Print report header. */
+ switch (type) {
+ case KFENCE_ERROR_OOB: {
+ const bool left_of_object = address < meta->addr;
+
+ pr_err("BUG: KFENCE: out-of-bounds %s in %pS\n\n", get_access_type(is_write),
+ (void *)stack_entries[skipnr]);
+ pr_err("Out-of-bounds %s at 0x%p (%luB %s of kfence-#%td):\n",
+ get_access_type(is_write), (void *)address,
+ left_of_object ? meta->addr - address : address - meta->addr,
+ left_of_object ? "left" : "right", object_index);
+ break;
+ }
+ case KFENCE_ERROR_UAF:
+ pr_err("BUG: KFENCE: use-after-free %s in %pS\n\n", get_access_type(is_write),
+ (void *)stack_entries[skipnr]);
+ pr_err("Use-after-free %s at 0x%p (in kfence-#%td):\n",
+ get_access_type(is_write), (void *)address, object_index);
+ break;
+ case KFENCE_ERROR_CORRUPTION:
+ pr_err("BUG: KFENCE: memory corruption in %pS\n\n", (void *)stack_entries[skipnr]);
+ pr_err("Corrupted memory at 0x%p ", (void *)address);
+ print_diff_canary(address, 16, meta);
+ pr_cont(" (in kfence-#%td):\n", object_index);
+ break;
+ case KFENCE_ERROR_INVALID:
+ pr_err("BUG: KFENCE: invalid %s in %pS\n\n", get_access_type(is_write),
+ (void *)stack_entries[skipnr]);
+ pr_err("Invalid %s at 0x%p:\n", get_access_type(is_write),
+ (void *)address);
+ break;
+ case KFENCE_ERROR_INVALID_FREE:
+ pr_err("BUG: KFENCE: invalid free in %pS\n\n", (void *)stack_entries[skipnr]);
+ pr_err("Invalid free of 0x%p (in kfence-#%td):\n", (void *)address,
+ object_index);
+ break;
+ }
+
+ /* Print stack trace and object info. */
+ stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr, 0);
+
+ if (meta) {
+ pr_err("\n");
+ kfence_print_object(NULL, meta);
+ }
+
+ /* Print report footer. */
+ pr_err("\n");
+ if (no_hash_pointers && regs)
+ show_regs(regs);
+ else
+ dump_stack_print_info(KERN_ERR);
+ trace_error_report_end(ERROR_DETECTOR_KFENCE, address);
+ pr_err("==================================================================\n");
+
+ lockdep_on();
+
+ check_panic_on_warn("KFENCE");
+
+ /* We encountered a memory safety error, taint the kernel! */
+ add_taint(TAINT_BAD_PAGE, LOCKDEP_STILL_OK);
+}
+
+#ifdef CONFIG_PRINTK
+static void kfence_to_kp_stack(const struct kfence_track *track, void **kp_stack)
+{
+ int i, j;
+
+ i = get_stack_skipnr(track->stack_entries, track->num_stack_entries, NULL);
+ for (j = 0; i < track->num_stack_entries && j < KS_ADDRS_COUNT; ++i, ++j)
+ kp_stack[j] = (void *)track->stack_entries[i];
+ if (j < KS_ADDRS_COUNT)
+ kp_stack[j] = NULL;
+}
+
+bool __kfence_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
+{
+ struct kfence_metadata *meta = addr_to_metadata((unsigned long)object);
+ unsigned long flags;
+
+ if (!meta)
+ return false;
+
+ /*
+ * If state is UNUSED at least show the pointer requested; the rest
+ * would be garbage data.
+ */
+ kpp->kp_ptr = object;
+
+ /* Requesting info an a never-used object is almost certainly a bug. */
+ if (WARN_ON(meta->state == KFENCE_OBJECT_UNUSED))
+ return true;
+
+ raw_spin_lock_irqsave(&meta->lock, flags);
+
+ kpp->kp_slab = slab;
+ kpp->kp_slab_cache = meta->cache;
+ kpp->kp_objp = (void *)meta->addr;
+ kfence_to_kp_stack(&meta->alloc_track, kpp->kp_stack);
+ if (meta->state == KFENCE_OBJECT_FREED)
+ kfence_to_kp_stack(&meta->free_track, kpp->kp_free_stack);
+ /* get_stack_skipnr() ensures the first entry is outside allocator. */
+ kpp->kp_ret = kpp->kp_stack[0];
+
+ raw_spin_unlock_irqrestore(&meta->lock, flags);
+
+ return true;
+}
+#endif