In the Linux kernel, the following vulnerability has been resolved: net: dsa: ar9331: register the mdiobus under devres As explained in commits: 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres") mdiobus_free() will panic when called from devm_mdiobus_free() <- devres_release_all() <- __device_release_driver(), and that mdiobus was not previously unregistered. The ar9331 is an MDIO device, so the initial set of constraints that I thought would cause this (I2C or SPI buses which call ->remove on ->shutdown) do not apply. But there is one more which applies here. If the DSA master itself is on a bus that calls ->remove from ->shutdown (like dpaa2-eth, which is on the fsl-mc bus), there is a device link between the switch and the DSA master, and device_links_unbind_consumers() will unbind the ar9331 switch driver on shutdown. So the same treatment must be applied to all DSA switch drivers, which is: either use devres for both the mdiobus allocation and registration, or don't use devres at all. The ar9331 driver doesn't have a complex code structure for mdiobus removal, so just replace of_mdiobus_register with the devres variant in order to be all-devres and ensure that we don't free a still-registered bus.

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: lock against ->sock changing during sysfs read ->sock can be set to NULL asynchronously unless ->recv_mutex is held. So it is important to hold that mutex. Otherwise a sysfs read can trigger an oops. Commit 17f09d3f619a ("SUNRPC: Check if the xprt is connected before handling sysfs reads") appears to attempt to fix this problem, but it only narrows the race window.

In the Linux kernel, the following vulnerability has been resolved: net: dsa: bcm_sf2: don't use devres for mdiobus As explained in commits: 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres") mdiobus_free() will panic when called from devm_mdiobus_free() <- devres_release_all() <- __device_release_driver(), and that mdiobus was not previously unregistered. The Starfighter 2 is a platform device, so the initial set of constraints that I thought would cause this (I2C or SPI buses which call ->remove on ->shutdown) do not apply. But there is one more which applies here. If the DSA master itself is on a bus that calls ->remove from ->shutdown (like dpaa2-eth, which is on the fsl-mc bus), there is a device link between the switch and the DSA master, and device_links_unbind_consumers() will unbind the bcm_sf2 switch driver on shutdown. So the same treatment must be applied to all DSA switch drivers, which is: either use devres for both the mdiobus allocation and registration, or don't use devres at all. The bcm_sf2 driver has the code structure in place for orderly mdiobus removal, so just replace devm_mdiobus_alloc() with the non-devres variant, and add manual free where necessary, to ensure that we don't let devres free a still-registered bus.

In the Linux kernel, the following vulnerability has been resolved: net: dsa: seville: register the mdiobus under devres As explained in commits: 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres") mdiobus_free() will panic when called from devm_mdiobus_free() <- devres_release_all() <- __device_release_driver(), and that mdiobus was not previously unregistered. The Seville VSC9959 switch is a platform device, so the initial set of constraints that I thought would cause this (I2C or SPI buses which call ->remove on ->shutdown) do not apply. But there is one more which applies here. If the DSA master itself is on a bus that calls ->remove from ->shutdown (like dpaa2-eth, which is on the fsl-mc bus), there is a device link between the switch and the DSA master, and device_links_unbind_consumers() will unbind the seville switch driver on shutdown. So the same treatment must be applied to all DSA switch drivers, which is: either use devres for both the mdiobus allocation and registration, or don't use devres at all. The seville driver has a code structure that could accommodate both the mdiobus_unregister and mdiobus_free calls, but it has an external dependency upon mscc_miim_setup() from mdio-mscc-miim.c, which calls devm_mdiobus_alloc_size() on its behalf. So rather than restructuring that, and exporting yet one more symbol mscc_miim_teardown(), let's work with devres and replace of_mdiobus_register with the devres variant. When we use all-devres, we can ensure that devres doesn't free a still-registered bus (it either runs both callbacks, or none).

In the Linux kernel, the following vulnerability has been resolved: net: dsa: felix: don't use devres for mdiobus As explained in commits: 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres") mdiobus_free() will panic when called from devm_mdiobus_free() <- devres_release_all() <- __device_release_driver(), and that mdiobus was not previously unregistered. The Felix VSC9959 switch is a PCI device, so the initial set of constraints that I thought would cause this (I2C or SPI buses which call ->remove on ->shutdown) do not apply. But there is one more which applies here. If the DSA master itself is on a bus that calls ->remove from ->shutdown (like dpaa2-eth, which is on the fsl-mc bus), there is a device link between the switch and the DSA master, and device_links_unbind_consumers() will unbind the felix switch driver on shutdown. So the same treatment must be applied to all DSA switch drivers, which is: either use devres for both the mdiobus allocation and registration, or don't use devres at all. The felix driver has the code structure in place for orderly mdiobus removal, so just replace devm_mdiobus_alloc_size() with the non-devres variant, and add manual free where necessary, to ensure that we don't let devres free a still-registered bus.

In the Linux kernel, the following vulnerability has been resolved: net: dsa: lantiq_gswip: don't use devres for mdiobus As explained in commits: 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres") mdiobus_free() will panic when called from devm_mdiobus_free() <- devres_release_all() <- __device_release_driver(), and that mdiobus was not previously unregistered. The GSWIP switch is a platform device, so the initial set of constraints that I thought would cause this (I2C or SPI buses which call ->remove on ->shutdown) do not apply. But there is one more which applies here. If the DSA master itself is on a bus that calls ->remove from ->shutdown (like dpaa2-eth, which is on the fsl-mc bus), there is a device link between the switch and the DSA master, and device_links_unbind_consumers() will unbind the GSWIP switch driver on shutdown. So the same treatment must be applied to all DSA switch drivers, which is: either use devres for both the mdiobus allocation and registration, or don't use devres at all. The gswip driver has the code structure in place for orderly mdiobus removal, so just replace devm_mdiobus_alloc() with the non-devres variant, and add manual free where necessary, to ensure that we don't let devres free a still-registered bus.

In the Linux kernel, the following vulnerability has been resolved: ibmvnic: don't release napi in __ibmvnic_open() If __ibmvnic_open() encounters an error such as when setting link state, it calls release_resources() which frees the napi structures needlessly. Instead, have __ibmvnic_open() only clean up the work it did so far (i.e. disable napi and irqs) and leave the rest to the callers. If caller of __ibmvnic_open() is ibmvnic_open(), it should release the resources immediately. If the caller is do_reset() or do_hard_reset(), they will release the resources on the next reset. This fixes following crash that occurred when running the drmgr command several times to add/remove a vnic interface: [102056] ibmvnic 30000003 env3: Disabling rx_scrq[6] irq [102056] ibmvnic 30000003 env3: Disabling rx_scrq[7] irq [102056] ibmvnic 30000003 env3: Replenished 8 pools Kernel attempted to read user page (10) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x00000010 Faulting instruction address: 0xc000000000a3c840 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries ... CPU: 9 PID: 102056 Comm: kworker/9:2 Kdump: loaded Not tainted 5.16.0-rc5-autotest-g6441998e2e37 #1 Workqueue: events_long __ibmvnic_reset [ibmvnic] NIP: c000000000a3c840 LR: c0080000029b5378 CTR: c000000000a3c820 REGS: c0000000548e37e0 TRAP: 0300 Not tainted (5.16.0-rc5-autotest-g6441998e2e37) MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 28248484 XER: 00000004 CFAR: c0080000029bdd24 DAR: 0000000000000010 DSISR: 40000000 IRQMASK: 0 GPR00: c0080000029b55d0 c0000000548e3a80 c0000000028f0200 0000000000000000 ... NIP [c000000000a3c840] napi_enable+0x20/0xc0 LR [c0080000029b5378] __ibmvnic_open+0xf0/0x430 [ibmvnic] Call Trace: [c0000000548e3a80] [0000000000000006] 0x6 (unreliable) [c0000000548e3ab0] [c0080000029b55d0] __ibmvnic_open+0x348/0x430 [ibmvnic] [c0000000548e3b40] [c0080000029bcc28] __ibmvnic_reset+0x500/0xdf0 [ibmvnic] [c0000000548e3c60] [c000000000176228] process_one_work+0x288/0x570 [c0000000548e3d00] [c000000000176588] worker_thread+0x78/0x660 [c0000000548e3da0] [c0000000001822f0] kthread+0x1c0/0x1d0 [c0000000548e3e10] [c00000000000cf64] ret_from_kernel_thread+0x5c/0x64 Instruction dump: 7d2948f8 792307e0 4e800020 60000000 3c4c01eb 384239e0 f821ffd1 39430010 38a0fff6 e92d1100 f9210028 39200000 <e9030010> f9010020 60420000 e9210020 ---[ end trace 5f8033b08fd27706 ]---

In the Linux kernel, the following vulnerability has been resolved: ipmr,ip6mr: acquire RTNL before calling ip[6]mr_free_table() on failure path ip[6]mr_free_table() can only be called under RTNL lock. RTNL: assertion failed at net/core/dev.c (10367) WARNING: CPU: 1 PID: 5890 at net/core/dev.c:10367 unregister_netdevice_many+0x1246/0x1850 net/core/dev.c:10367 Modules linked in: CPU: 1 PID: 5890 Comm: syz-executor.2 Not tainted 5.16.0-syzkaller-11627-g422ee58dc0ef #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:unregister_netdevice_many+0x1246/0x1850 net/core/dev.c:10367 Code: 0f 85 9b ee ff ff e8 69 07 4b fa ba 7f 28 00 00 48 c7 c6 00 90 ae 8a 48 c7 c7 40 90 ae 8a c6 05 6d b1 51 06 01 e8 8c 90 d8 01 <0f> 0b e9 70 ee ff ff e8 3e 07 4b fa 4c 89 e7 e8 86 2a 59 fa e9 ee RSP: 0018:ffffc900046ff6e0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888050f51d00 RSI: ffffffff815fa008 RDI: fffff520008dfece RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815f3d6e R11: 0000000000000000 R12: 00000000fffffff4 R13: dffffc0000000000 R14: ffffc900046ff750 R15: ffff88807b7dc000 FS: 00007f4ab736e700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fee0b4f8990 CR3: 000000001e7d2000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> mroute_clean_tables+0x244/0xb40 net/ipv6/ip6mr.c:1509 ip6mr_free_table net/ipv6/ip6mr.c:389 [inline] ip6mr_rules_init net/ipv6/ip6mr.c:246 [inline] ip6mr_net_init net/ipv6/ip6mr.c:1306 [inline] ip6mr_net_init+0x3f0/0x4e0 net/ipv6/ip6mr.c:1298 ops_init+0xaf/0x470 net/core/net_namespace.c:140 setup_net+0x54f/0xbb0 net/core/net_namespace.c:331 copy_net_ns+0x318/0x760 net/core/net_namespace.c:475 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178 copy_process+0x2e0c/0x7300 kernel/fork.c:2167 kernel_clone+0xe7/0xab0 kernel/fork.c:2555 __do_sys_clone+0xc8/0x110 kernel/fork.c:2672 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f4ab89f9059 Code: Unable to access opcode bytes at RIP 0x7f4ab89f902f. RSP: 002b:00007f4ab736e118 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f4ab8b0bf60 RCX: 00007f4ab89f9059 RDX: 0000000020000280 RSI: 0000000020000270 RDI: 0000000040200000 RBP: 00007f4ab8a5308d R08: 0000000020000300 R09: 0000000020000300 R10: 00000000200002c0 R11: 0000000000000206 R12: 0000000000000000 R13: 00007ffc3977cc1f R14: 00007f4ab736e300 R15: 0000000000022000 </TASK>

In the Linux kernel, the following vulnerability has been resolved: net: fix a memleak when uncloning an skb dst and its metadata When uncloning an skb dst and its associated metadata, a new dst+metadata is allocated and later replaces the old one in the skb. This is helpful to have a non-shared dst+metadata attached to a specific skb. The issue is the uncloned dst+metadata is initialized with a refcount of 1, which is increased to 2 before attaching it to the skb. When tun_dst_unclone returns, the dst+metadata is only referenced from a single place (the skb) while its refcount is 2. Its refcount will never drop to 0 (when the skb is consumed), leading to a memory leak. Fix this by removing the call to dst_hold in tun_dst_unclone, as the dst+metadata refcount is already 1.

In the Linux kernel, the following vulnerability has been resolved: net: dsa: fix panic when DSA master device unbinds on shutdown Rafael reports that on a system with LX2160A and Marvell DSA switches, if a reboot occurs while the DSA master (dpaa2-eth) is up, the following panic can be seen: systemd-shutdown[1]: Rebooting. Unable to handle kernel paging request at virtual address 00a0000800000041 [00a0000800000041] address between user and kernel address ranges Internal error: Oops: 96000004 [#1] PREEMPT SMP CPU: 6 PID: 1 Comm: systemd-shutdow Not tainted 5.16.5-00042-g8f5585009b24 #32 pc : dsa_slave_netdevice_event+0x130/0x3e4 lr : raw_notifier_call_chain+0x50/0x6c Call trace: dsa_slave_netdevice_event+0x130/0x3e4 raw_notifier_call_chain+0x50/0x6c call_netdevice_notifiers_info+0x54/0xa0 __dev_close_many+0x50/0x130 dev_close_many+0x84/0x120 unregister_netdevice_many+0x130/0x710 unregister_netdevice_queue+0x8c/0xd0 unregister_netdev+0x20/0x30 dpaa2_eth_remove+0x68/0x190 fsl_mc_driver_remove+0x20/0x5c __device_release_driver+0x21c/0x220 device_release_driver_internal+0xac/0xb0 device_links_unbind_consumers+0xd4/0x100 __device_release_driver+0x94/0x220 device_release_driver+0x28/0x40 bus_remove_device+0x118/0x124 device_del+0x174/0x420 fsl_mc_device_remove+0x24/0x40 __fsl_mc_device_remove+0xc/0x20 device_for_each_child+0x58/0xa0 dprc_remove+0x90/0xb0 fsl_mc_driver_remove+0x20/0x5c __device_release_driver+0x21c/0x220 device_release_driver+0x28/0x40 bus_remove_device+0x118/0x124 device_del+0x174/0x420 fsl_mc_bus_remove+0x80/0x100 fsl_mc_bus_shutdown+0xc/0x1c platform_shutdown+0x20/0x30 device_shutdown+0x154/0x330 __do_sys_reboot+0x1cc/0x250 __arm64_sys_reboot+0x20/0x30 invoke_syscall.constprop.0+0x4c/0xe0 do_el0_svc+0x4c/0x150 el0_svc+0x24/0xb0 el0t_64_sync_handler+0xa8/0xb0 el0t_64_sync+0x178/0x17c It can be seen from the stack trace that the problem is that the deregistration of the master causes a dev_close(), which gets notified as NETDEV_GOING_DOWN to dsa_slave_netdevice_event(). But dsa_switch_shutdown() has already run, and this has unregistered the DSA slave interfaces, and yet, the NETDEV_GOING_DOWN handler attempts to call dev_close_many() on those slave interfaces, leading to the problem. The previous attempt to avoid the NETDEV_GOING_DOWN on the master after dsa_switch_shutdown() was called seems improper. Unregistering the slave interfaces is unnecessary and unhelpful. Instead, after the slaves have stopped being uppers of the DSA master, we can now reset to NULL the master->dsa_ptr pointer, which will make DSA start ignoring all future notifier events on the master.

In the Linux kernel, the following vulnerability has been resolved: ice: Fix KASAN error in LAG NETDEV_UNREGISTER handler Currently, the same handler is called for both a NETDEV_BONDING_INFO LAG unlink notification as for a NETDEV_UNREGISTER call. This is causing a problem though, since the netdev_notifier_info passed has a different structure depending on which event is passed. The problem manifests as a call trace from a BUG: KASAN stack-out-of-bounds error. Fix this by creating a handler specific to NETDEV_UNREGISTER that only is passed valid elements in the netdev_notifier_info struct for the NETDEV_UNREGISTER event. Also included is the removal of an unbalanced dev_put on the peer_netdev and related braces.

In the Linux kernel, the following vulnerability has been resolved: eeprom: ee1004: limit i2c reads to I2C_SMBUS_BLOCK_MAX Commit effa453168a7 ("i2c: i801: Don't silently correct invalid transfer size") revealed that ee1004_eeprom_read() did not properly limit how many bytes to read at once. In particular, i2c_smbus_read_i2c_block_data_or_emulated() takes the length to read as an u8. If count == 256 after taking into account the offset and page boundary, the cast to u8 overflows. And this is common when user space tries to read the entire EEPROM at once. To fix it, limit each read to I2C_SMBUS_BLOCK_MAX (32) bytes, already the maximum length i2c_smbus_read_i2c_block_data_or_emulated() allows.

In the Linux kernel, the following vulnerability has been resolved: net: usb: ax88179_178a: Fix out-of-bounds accesses in RX fixup ax88179_rx_fixup() contains several out-of-bounds accesses that can be triggered by a malicious (or defective) USB device, in particular: - The metadata array (hdr_off..hdr_off+2*pkt_cnt) can be out of bounds, causing OOB reads and (on big-endian systems) OOB endianness flips. - A packet can overlap the metadata array, causing a later OOB endianness flip to corrupt data used by a cloned SKB that has already been handed off into the network stack. - A packet SKB can be constructed whose tail is far beyond its end, causing out-of-bounds heap data to be considered part of the SKB's data. I have tested that this can be used by a malicious USB device to send a bogus ICMPv6 Echo Request and receive an ICMPv6 Echo Reply in response that contains random kernel heap data. It's probably also possible to get OOB writes from this on a little-endian system somehow - maybe by triggering skb_cow() via IP options processing -, but I haven't tested that.

In the Linux kernel, the following vulnerability has been resolved: vt_ioctl: fix array_index_nospec in vt_setactivate array_index_nospec ensures that an out-of-bounds value is set to zero on the transient path. Decreasing the value by one afterwards causes a transient integer underflow. vsa.console should be decreased first and then sanitized with array_index_nospec. Kasper Acknowledgements: Jakob Koschel, Brian Johannesmeyer, Kaveh Razavi, Herbert Bos, Cristiano Giuffrida from the VUSec group at VU Amsterdam.

In the Linux kernel, the following vulnerability has been resolved: phy: ti: Fix missing sentinel for clk_div_table _get_table_maxdiv() tries to access "clk_div_table" array out of bound defined in phy-j721e-wiz.c. Add a sentinel entry to prevent the following global-out-of-bounds error reported by enabling KASAN. [ 9.552392] BUG: KASAN: global-out-of-bounds in _get_maxdiv+0xc0/0x148 [ 9.558948] Read of size 4 at addr ffff8000095b25a4 by task kworker/u4:1/38 [ 9.565926] [ 9.567441] CPU: 1 PID: 38 Comm: kworker/u4:1 Not tainted 5.16.0-116492-gdaadb3bd0e8d-dirty #360 [ 9.576242] Hardware name: Texas Instruments J721e EVM (DT) [ 9.581832] Workqueue: events_unbound deferred_probe_work_func [ 9.587708] Call trace: [ 9.590174] dump_backtrace+0x20c/0x218 [ 9.594038] show_stack+0x18/0x68 [ 9.597375] dump_stack_lvl+0x9c/0xd8 [ 9.601062] print_address_description.constprop.0+0x78/0x334 [ 9.606830] kasan_report+0x1f0/0x260 [ 9.610517] __asan_load4+0x9c/0xd8 [ 9.614030] _get_maxdiv+0xc0/0x148 [ 9.617540] divider_determine_rate+0x88/0x488 [ 9.622005] divider_round_rate_parent+0xc8/0x124 [ 9.626729] wiz_clk_div_round_rate+0x54/0x68 [ 9.631113] clk_core_determine_round_nolock+0x124/0x158 [ 9.636448] clk_core_round_rate_nolock+0x68/0x138 [ 9.641260] clk_core_set_rate_nolock+0x268/0x3a8 [ 9.645987] clk_set_rate+0x50/0xa8 [ 9.649499] cdns_sierra_phy_init+0x88/0x248 [ 9.653794] phy_init+0x98/0x108 [ 9.657046] cdns_pcie_enable_phy+0xa0/0x170 [ 9.661340] cdns_pcie_init_phy+0x250/0x2b0 [ 9.665546] j721e_pcie_probe+0x4b8/0x798 [ 9.669579] platform_probe+0x8c/0x108 [ 9.673350] really_probe+0x114/0x630 [ 9.677037] __driver_probe_device+0x18c/0x220 [ 9.681505] driver_probe_device+0xac/0x150 [ 9.685712] __device_attach_driver+0xec/0x170 [ 9.690178] bus_for_each_drv+0xf0/0x158 [ 9.694124] __device_attach+0x184/0x210 [ 9.698070] device_initial_probe+0x14/0x20 [ 9.702277] bus_probe_device+0xec/0x100 [ 9.706223] deferred_probe_work_func+0x124/0x180 [ 9.710951] process_one_work+0x4b0/0xbc0 [ 9.714983] worker_thread+0x74/0x5d0 [ 9.718668] kthread+0x214/0x230 [ 9.721919] ret_from_fork+0x10/0x20 [ 9.725520] [ 9.727032] The buggy address belongs to the variable: [ 9.732183] clk_div_table+0x24/0x440

In the Linux kernel, the following vulnerability has been resolved: fs/proc: task_mmu.c: don't read mapcount for migration entry The syzbot reported the below BUG: kernel BUG at include/linux/page-flags.h:785! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 4392 Comm: syz-executor560 Not tainted 5.16.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:PageDoubleMap include/linux/page-flags.h:785 [inline] RIP: 0010:__page_mapcount+0x2d2/0x350 mm/util.c:744 Call Trace: page_mapcount include/linux/mm.h:837 [inline] smaps_account+0x470/0xb10 fs/proc/task_mmu.c:466 smaps_pte_entry fs/proc/task_mmu.c:538 [inline] smaps_pte_range+0x611/0x1250 fs/proc/task_mmu.c:601 walk_pmd_range mm/pagewalk.c:128 [inline] walk_pud_range mm/pagewalk.c:205 [inline] walk_p4d_range mm/pagewalk.c:240 [inline] walk_pgd_range mm/pagewalk.c:277 [inline] __walk_page_range+0xe23/0x1ea0 mm/pagewalk.c:379 walk_page_vma+0x277/0x350 mm/pagewalk.c:530 smap_gather_stats.part.0+0x148/0x260 fs/proc/task_mmu.c:768 smap_gather_stats fs/proc/task_mmu.c:741 [inline] show_smap+0xc6/0x440 fs/proc/task_mmu.c:822 seq_read_iter+0xbb0/0x1240 fs/seq_file.c:272 seq_read+0x3e0/0x5b0 fs/seq_file.c:162 vfs_read+0x1b5/0x600 fs/read_write.c:479 ksys_read+0x12d/0x250 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The reproducer was trying to read /proc/$PID/smaps when calling MADV_FREE at the mean time. MADV_FREE may split THPs if it is called for partial THP. It may trigger the below race: CPU A CPU B ----- ----- smaps walk: MADV_FREE: page_mapcount() PageCompound() split_huge_page() page = compound_head(page) PageDoubleMap(page) When calling PageDoubleMap() this page is not a tail page of THP anymore so the BUG is triggered. This could be fixed by elevated refcount of the page before calling mapcount, but that would prevent it from counting migration entries, and it seems overkilling because the race just could happen when PMD is split so all PTE entries of tail pages are actually migration entries, and smaps_account() does treat migration entries as mapcount == 1 as Kirill pointed out. Add a new parameter for smaps_account() to tell this entry is migration entry then skip calling page_mapcount(). Don't skip getting mapcount for device private entries since they do track references with mapcount. Pagemap also has the similar issue although it was not reported. Fixed it as well. [shy828301@gmail.com: v4] Link: https://lkml.kernel.org/r/20220203182641.824731-1-shy828301@gmail.com [nathan@kernel.org: avoid unused variable warning in pagemap_pmd_range()] Link: https://lkml.kernel.org/r/20220207171049.1102239-1-nathan@kernel.org

In the Linux kernel, the following vulnerability has been resolved: iio: buffer: Fix file related error handling in IIO_BUFFER_GET_FD_IOCTL If we fail to copy the just created file descriptor to userland, we try to clean up by putting back 'fd' and freeing 'ib'. The code uses put_unused_fd() for the former which is wrong, as the file descriptor was already published by fd_install() which gets called internally by anon_inode_getfd(). This makes the error handling code leaving a half cleaned up file descriptor table around and a partially destructed 'file' object, allowing userland to play use-after-free tricks on us, by abusing the still usable fd and making the code operate on a dangling 'file->private_data' pointer. Instead of leaving the kernel in a partially corrupted state, don't attempt to explicitly clean up and leave this to the process exit path that'll release any still valid fds, including the one created by the previous call to anon_inode_getfd(). Simply return -EFAULT to indicate the error.

In the Linux kernel, the following vulnerability has been resolved: mm: vmscan: remove deadlock due to throttling failing to make progress A soft lockup bug in kcompactd was reported in a private bugzilla with the following visible in dmesg; watchdog: BUG: soft lockup - CPU#33 stuck for 26s! [kcompactd0:479] watchdog: BUG: soft lockup - CPU#33 stuck for 52s! [kcompactd0:479] watchdog: BUG: soft lockup - CPU#33 stuck for 78s! [kcompactd0:479] watchdog: BUG: soft lockup - CPU#33 stuck for 104s! [kcompactd0:479] The machine had 256G of RAM with no swap and an earlier failed allocation indicated that node 0 where kcompactd was run was potentially unreclaimable; Node 0 active_anon:29355112kB inactive_anon:2913528kB active_file:0kB inactive_file:0kB unevictable:64kB isolated(anon):0kB isolated(file):0kB mapped:8kB dirty:0kB writeback:0kB shmem:26780kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 23480320kB writeback_tmp:0kB kernel_stack:2272kB pagetables:24500kB all_unreclaimable? yes Vlastimil Babka investigated a crash dump and found that a task migrating pages was trying to drain PCP lists; PID: 52922 TASK: ffff969f820e5000 CPU: 19 COMMAND: "kworker/u128:3" Call Trace: __schedule schedule schedule_timeout wait_for_completion __flush_work __drain_all_pages __alloc_pages_slowpath.constprop.114 __alloc_pages alloc_migration_target migrate_pages migrate_to_node do_migrate_pages cpuset_migrate_mm_workfn process_one_work worker_thread kthread ret_from_fork This failure is specific to CONFIG_PREEMPT=n builds. The root of the problem is that kcompact0 is not rescheduling on a CPU while a task that has isolated a large number of the pages from the LRU is waiting on kcompact0 to reschedule so the pages can be released. While shrink_inactive_list() only loops once around too_many_isolated, reclaim can continue without rescheduling if sc->skipped_deactivate == 1 which could happen if there was no file LRU and the inactive anon list was not low.

In the Linux kernel, the following vulnerability has been resolved: perf: Fix list corruption in perf_cgroup_switch() There's list corruption on cgrp_cpuctx_list. This happens on the following path: perf_cgroup_switch: list_for_each_entry(cgrp_cpuctx_list) cpu_ctx_sched_in ctx_sched_in ctx_pinned_sched_in merge_sched_in perf_cgroup_event_disable: remove the event from the list Use list_for_each_entry_safe() to allow removing an entry during iteration.

In the Linux kernel, the following vulnerability has been resolved: s390/cio: verify the driver availability for path_event call If no driver is attached to a device or the driver does not provide the path_event function, an FCES path-event on this device could end up in a kernel-panic. Verify the driver availability before the path_event function call.