Example of using function casting by rlmenge · Pull Request #2 · rlmenge/linux

rlmenge · 2023-09-20T21:33:24Z

More info
https://stackoverflow.com/questions/559581/casting-a-function-pointer-to-another-type/14044244#14044244

More info https://stackoverflow.com/questions/559581/casting-a-function-pointer-to-another-type/14044244#14044244

Sockmap and sockhash maps are a collection of psocks that are objects representing a socket plus a set of metadata needed to manage the BPF programs associated with the socket. These maps use the stab->lock to protect from concurrent operations on the maps, e.g. trying to insert to objects into the array at the same time in the same slot. Additionally, a sockhash map has a bucket lock to protect iteration and insert/delete into the hash entry. Each psock has a psock->link which is a linked list of all the maps that a psock is attached to. This allows a psock (socket) to be included in multiple sockmap and sockhash maps. This linked list is protected the psock->link_lock. They _must_ be nested correctly to avoid deadlock: lock(stab->lock) : do BPF map operations and psock insert/delete lock(psock->link_lock) : add map to psock linked list of maps unlock(psock->link_lock) unlock(stab->lock) For non PREEMPT_RT kernels both raw_spin_lock_t and spin_lock_t are guaranteed to not sleep. But, with PREEMPT_RT kernels the spin_lock_t variants may sleep. In the current code we have many patterns like this: rcu_critical_section: raw_spin_lock(stab->lock) spin_lock(psock->link_lock) <- may sleep ouch spin_unlock(psock->link_lock) raw_spin_unlock(stab->lock) rcu_critical_section Nesting spin_lock() inside a raw_spin_lock() violates locking rules for PREEMPT_RT kernels. And additionally we do alloc(GFP_ATOMICS) inside the stab->lock, but those might sleep on PREEMPT_RT kernels. The result is splats like this: ./test_progs -t sockmap_basic [ 33.344330] bpf_testmod: loading out-of-tree module taints kernel. [ 33.441933] [ 33.442089] ============================= [ 33.442421] [ BUG: Invalid wait context ] [ 33.442763] 6.5.0-rc5-01731-gec0ded2e0282 #4958 Tainted: G O [ 33.443320] ----------------------------- [ 33.443624] test_progs/2073 is trying to lock: [ 33.443960] ffff888102a1c290 (&psock->link_lock){....}-{3:3}, at: sock_map_update_common+0x2c2/0x3d0 [ 33.444636] other info that might help us debug this: [ 33.444991] context-{5:5} [ 33.445183] 3 locks held by test_progs/2073: [ 33.445498] #0: ffff88811a208d30 (sk_lock-AF_INET){+.+.}-{0:0}, at: sock_map_update_elem_sys+0xff/0x330 [ 33.446159] #1: ffffffff842539e0 (rcu_read_lock){....}-{1:3}, at: sock_map_update_elem_sys+0xf5/0x330 [ 33.446809] #2: ffff88810d687240 (&stab->lock){+...}-{2:2}, at: sock_map_update_common+0x177/0x3d0 [ 33.447445] stack backtrace: [ 33.447655] CPU: 10 PID To fix observe we can't readily remove the allocations (for that we would need to use/create something similar to bpf_map_alloc). So convert raw_spin_lock_t to spin_lock_t. We note that sock_map_update that would trigger the allocate and potential sleep is only allowed through sys_bpf ops and via sock_ops which precludes hw interrupts and low level atomic sections in RT preempt kernel. On non RT preempt kernel there are no changes here and spin locks sections and alloc(GFP_ATOMIC) are still not sleepable. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230830053517.166611-1-john.fastabend@gmail.com

…es_lock __dma_entry_alloc_check_leak() calls into printk -> serial console output (qcom geni) and grabs port->lock under free_entries_lock spin lock, which is a reverse locking dependency chain as qcom_geni IRQ handler can call into dma-debug code and grab free_entries_lock under port->lock. Move __dma_entry_alloc_check_leak() call out of free_entries_lock scope so that we don't acquire serial console's port->lock under it. Trimmed-down lockdep splat: The existing dependency chain (in reverse order) is: -> #2 (free_entries_lock){-.-.}-{2:2}: _raw_spin_lock_irqsave+0x60/0x80 dma_entry_alloc+0x38/0x110 debug_dma_map_page+0x60/0xf8 dma_map_page_attrs+0x1e0/0x230 dma_map_single_attrs.constprop.0+0x6c/0xc8 geni_se_rx_dma_prep+0x40/0xcc qcom_geni_serial_isr+0x310/0x510 __handle_irq_event_percpu+0x110/0x244 handle_irq_event_percpu+0x20/0x54 handle_irq_event+0x50/0x88 handle_fasteoi_irq+0xa4/0xcc handle_irq_desc+0x28/0x40 generic_handle_domain_irq+0x24/0x30 gic_handle_irq+0xc4/0x148 do_interrupt_handler+0xa4/0xb0 el1_interrupt+0x34/0x64 el1h_64_irq_handler+0x18/0x24 el1h_64_irq+0x64/0x68 arch_local_irq_enable+0x4/0x8 ____do_softirq+0x18/0x24 ... -> #1 (&port_lock_key){-.-.}-{2:2}: _raw_spin_lock_irqsave+0x60/0x80 qcom_geni_serial_console_write+0x184/0x1dc console_flush_all+0x344/0x454 console_unlock+0x94/0xf0 vprintk_emit+0x238/0x24c vprintk_default+0x3c/0x48 vprintk+0xb4/0xbc _printk+0x68/0x90 register_console+0x230/0x38c uart_add_one_port+0x338/0x494 qcom_geni_serial_probe+0x390/0x424 platform_probe+0x70/0xc0 really_probe+0x148/0x280 __driver_probe_device+0xfc/0x114 driver_probe_device+0x44/0x100 __device_attach_driver+0x64/0xdc bus_for_each_drv+0xb0/0xd8 __device_attach+0xe4/0x140 device_initial_probe+0x1c/0x28 bus_probe_device+0x44/0xb0 device_add+0x538/0x668 of_device_add+0x44/0x50 of_platform_device_create_pdata+0x94/0xc8 of_platform_bus_create+0x270/0x304 of_platform_populate+0xac/0xc4 devm_of_platform_populate+0x60/0xac geni_se_probe+0x154/0x160 platform_probe+0x70/0xc0 ... -> #0 (console_owner){-...}-{0:0}: __lock_acquire+0xdf8/0x109c lock_acquire+0x234/0x284 console_flush_all+0x330/0x454 console_unlock+0x94/0xf0 vprintk_emit+0x238/0x24c vprintk_default+0x3c/0x48 vprintk+0xb4/0xbc _printk+0x68/0x90 dma_entry_alloc+0xb4/0x110 debug_dma_map_sg+0xdc/0x2f8 __dma_map_sg_attrs+0xac/0xe4 dma_map_sgtable+0x30/0x4c get_pages+0x1d4/0x1e4 [msm] msm_gem_pin_pages_locked+0x38/0xac [msm] msm_gem_pin_vma_locked+0x58/0x88 [msm] msm_ioctl_gem_submit+0xde4/0x13ac [msm] drm_ioctl_kernel+0xe0/0x15c drm_ioctl+0x2e8/0x3f4 vfs_ioctl+0x30/0x50 ... Chain exists of: console_owner --> &port_lock_key --> free_entries_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(free_entries_lock); lock(&port_lock_key); lock(free_entries_lock); lock(console_owner); *** DEADLOCK *** Call trace: dump_backtrace+0xb4/0xf0 show_stack+0x20/0x30 dump_stack_lvl+0x60/0x84 dump_stack+0x18/0x24 print_circular_bug+0x1cc/0x234 check_noncircular+0x78/0xac __lock_acquire+0xdf8/0x109c lock_acquire+0x234/0x284 console_flush_all+0x330/0x454 console_unlock+0x94/0xf0 vprintk_emit+0x238/0x24c vprintk_default+0x3c/0x48 vprintk+0xb4/0xbc _printk+0x68/0x90 dma_entry_alloc+0xb4/0x110 debug_dma_map_sg+0xdc/0x2f8 __dma_map_sg_attrs+0xac/0xe4 dma_map_sgtable+0x30/0x4c get_pages+0x1d4/0x1e4 [msm] msm_gem_pin_pages_locked+0x38/0xac [msm] msm_gem_pin_vma_locked+0x58/0x88 [msm] msm_ioctl_gem_submit+0xde4/0x13ac [msm] drm_ioctl_kernel+0xe0/0x15c drm_ioctl+0x2e8/0x3f4 vfs_ioctl+0x30/0x50 ... Reported-by: Rob Clark <robdclark@chromium.org> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Acked-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Christoph Hellwig <hch@lst.de>

…git/vgupta/arc Pull ARC updates from Vineet Gupta: - fixes for -Wmissing-prototype warnings - missing compiler barrier in relaxed atomics - some uaccess simplification, declutter - removal of massive glocal struct cpuinfo_arc from bootlog code - __switch_to consolidation (removal of inline asm variant) - use GP to cache task pointer (vs. r25) - misc rework of entry code * tag 'arc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (24 commits) ARC: boot log: fix warning arc: Explicitly include correct DT includes ARC: pt_regs: create seperate type for ecr ARCv2: entry: rearrange pt_regs slightly ARC: entry: replace 8 byte ADD.ne with 4 byte ADD2.ne ARC: entry: replace 8 byte OR with 4 byte BSET ARC: entry: Add more common chores to EXCEPTION_PROLOGUE ARC: entry: EV_MachineCheck dont re-read ECR ARC: entry: ARcompact EV_ProtV to use r10 directly ARC: entry: rework (non-functional) ARC: __switch_to: move ksp to thread_info from thread_struct ARC: __switch_to: asm with dwarf ops (vs. inline asm) ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp ARC: entry: use gp to cache task pointer (vs. r25) ARC: boot log: eliminate struct cpuinfo_arc #4: boot log per ISA ARC: boot log: eliminate struct cpuinfo_arc #3: don't export ARC: boot log: eliminate struct cpuinfo_arc #2: cache ARC: boot log: eliminate struct cpuinfo_arc #1: mm ARCv2: memset: don't prefetch for len == 0 which happens a alot ARC: uaccess: elide unaliged handling if hardware supports ...

Currently, for double invoke call_rcu(), will dump rcu_head objects memory info, if the objects is not allocated from the slab allocator, the vmalloc_dump_obj() will be invoke and the vmap_area_lock spinlock need to be held, since the call_rcu() can be invoked in interrupt context, therefore, there is a possibility of spinlock deadlock scenarios. And in Preempt-RT kernel, the rcutorture test also trigger the following lockdep warning: BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper/0 preempt_count: 1, expected: 0 RCU nest depth: 1, expected: 1 3 locks held by swapper/0/1: #0: ffffffffb534ee80 (fullstop_mutex){+.+.}-{4:4}, at: torture_init_begin+0x24/0xa0 #1: ffffffffb5307940 (rcu_read_lock){....}-{1:3}, at: rcu_torture_init+0x1ec7/0x2370 #2: ffffffffb536af40 (vmap_area_lock){+.+.}-{3:3}, at: find_vmap_area+0x1f/0x70 irq event stamp: 565512 hardirqs last enabled at (565511): [<ffffffffb379b138>] __call_rcu_common+0x218/0x940 hardirqs last disabled at (565512): [<ffffffffb5804262>] rcu_torture_init+0x20b2/0x2370 softirqs last enabled at (399112): [<ffffffffb36b2586>] __local_bh_enable_ip+0x126/0x170 softirqs last disabled at (399106): [<ffffffffb43fef59>] inet_register_protosw+0x9/0x1d0 Preemption disabled at: [<ffffffffb58040c3>] rcu_torture_init+0x1f13/0x2370 CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.5.0-rc4-rt2-yocto-preempt-rt+ Rust-for-Linux#15 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x68/0xb0 dump_stack+0x14/0x20 __might_resched+0x1aa/0x280 ? __pfx_rcu_torture_err_cb+0x10/0x10 rt_spin_lock+0x53/0x130 ? find_vmap_area+0x1f/0x70 find_vmap_area+0x1f/0x70 vmalloc_dump_obj+0x20/0x60 mem_dump_obj+0x22/0x90 __call_rcu_common+0x5bf/0x940 ? debug_smp_processor_id+0x1b/0x30 call_rcu_hurry+0x14/0x20 rcu_torture_init+0x1f82/0x2370 ? __pfx_rcu_torture_leak_cb+0x10/0x10 ? __pfx_rcu_torture_leak_cb+0x10/0x10 ? __pfx_rcu_torture_init+0x10/0x10 do_one_initcall+0x6c/0x300 ? debug_smp_processor_id+0x1b/0x30 kernel_init_freeable+0x2b9/0x540 ? __pfx_kernel_init+0x10/0x10 kernel_init+0x1f/0x150 ret_from_fork+0x40/0x50 ? __pfx_kernel_init+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> The previous patch fixes this by using the deadlock-safe best-effort version of find_vm_area. However, in case of failure print the fact that the pointer was a vmalloc pointer so that we print at least something. Link: https://lkml.kernel.org/r/20230904180806.1002832-2-joel@joelfernandes.org Fixes: 98f1808 ("mm: Make mem_dump_obj() handle vmalloc() memory") Signed-off-by: Zqiang <qiang.zhang1211@gmail.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Reported-by: Zhen Lei <thunder.leizhen@huaweicloud.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

…/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 6.16, take #2 - Rework of system register accessors for system registers that are directly writen to memory, so that sanitisation of the in-memory value happens at the correct time (after the read, or before the write). For convenience, RMW-style accessors are also provided. - Multiple fixes for the so-called "arch-timer-edge-cases' selftest, which was always broken.

As-per the SBI specification, an SBI remote fence operation applies to the entire address space if either: 1) start_addr and size are both 0 2) size is equal to 2^XLEN-1 >From the above, only #1 is checked by SBI SFENCE calls so fix the size parameter check in SBI SFENCE calls to cover #2 as well. Fixes: 13acfec ("RISC-V: KVM: Add remote HFENCE functions based on VCPU requests") Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <apatel@ventanamicro.com> Link: https://lore.kernel.org/r/20250605061458.196003-2-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>

This patch fixes an issue seen in a large-scale deployment under heavy incoming pkts where the aRFS flow wrongly matches a flow and reprograms the NIC with wrong settings. That mis-steering causes RX-path latency spikes and noisy neighbor effects when many connections collide on the same hash (some of our production servers have 20-30K connections). set_rps_cpu() calls ndo_rx_flow_steer() with flow_id that is calculated by hashing the skb sized by the per rx-queue table size. This results in multiple connections (even across different rx-queues) getting the same hash value. The driver steer function modifies the wrong flow to use this rx-queue, e.g.: Flow#1 is first added: Flow#1: <ip1, port1, ip2, port2>, Hash 'h', q#10 Later when a new flow needs to be added: Flow#2: <ip3, port3, ip4, port4>, Hash 'h', q#20 The driver finds the hash 'h' from Flow#1 and updates it to use q#20. This results in both flows getting un-optimized - packets for Flow#1 goes to q#20, and then reprogrammed back to q#10 later and so on; and Flow #2 programming is never done as Flow#1 is matched first for all misses. Many flows may wrongly share the same hash and reprogram rules of the original flow each with their own q#. Tested on two 144-core servers with 16K netperf sessions for 180s. Netperf clients are pinned to cores 0-71 sequentially (so that wrong packets on q#s 72-143 can be measured). IRQs are set 1:1 for queues -> CPUs, enable XPS, enable aRFS (global value is 144 * rps_flow_cnt). Test notes about results from ice_rx_flow_steer(): --------------------------------------------------- 1. "Skip:" counter increments here: if (fltr_info->q_index == rxq_idx || arfs_entry->fltr_state != ICE_ARFS_ACTIVE) goto out; 2. "Add:" counter increments here: ret = arfs_entry->fltr_info.fltr_id; INIT_HLIST_NODE(&arfs_entry->list_entry); 3. "Update:" counter increments here: /* update the queue to forward to on an already existing flow */ Runtime comparison: original code vs with the patch for different rps_flow_cnt values. +-------------------------------+--------------+--------------+ | rps_flow_cnt | 512 | 2048 | +-------------------------------+--------------+--------------+ | Ratio of Pkts on Good:Bad q's | 214 vs 822K | 1.1M vs 980K | | Avoid wrong aRFS programming | 0 vs 310K | 0 vs 30K | | CPU User | 216 vs 183 | 216 vs 206 | | CPU System | 1441 vs 1171 | 1447 vs 1320 | | CPU Softirq | 1245 vs 920 | 1238 vs 961 | | CPU Total | 29 vs 22.7 | 29 vs 24.9 | | aRFS Update | 533K vs 59 | 521K vs 32 | | aRFS Skip | 82M vs 77M | 7.2M vs 4.5M | +-------------------------------+--------------+--------------+ A separate TCP_STREAM and TCP_RR with 1,4,8,16,64,128,256,512 connections showed no performance degradation. Some points on the patch/aRFS behavior: 1. Enabling full tuple matching ensures flows are always correctly matched, even with smaller hash sizes. 2. 5-6% drop in CPU utilization as the packets arrive at the correct CPUs and fewer calls to driver for programming on misses. 3. Larger hash tables reduces mis-steering due to more unique flow hashes, but still has clashes. However, with larger per-device rps_flow_cnt, old flows take more time to expire and new aRFS flows cannot be added if h/w limits are reached (rps_may_expire_flow() succeeds when 10*rps_flow_cnt pkts have been processed by this cpu that are not part of the flow). Fixes: 28bf267 ("ice: Implement aRFS") Signed-off-by: Krishna Kumar <krikku@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel) Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

syzkaller reported a null-ptr-deref in sock_omalloc() while allocating a CALIPSO option. [0] The NULL is of struct sock, which was fetched by sk_to_full_sk() in calipso_req_setattr(). Since commit a1a5344 ("tcp: avoid two atomic ops for syncookies"), reqsk->rsk_listener could be NULL when SYN Cookie is returned to its client, as hinted by the leading SYN Cookie log. Here are 3 options to fix the bug: 1) Return 0 in calipso_req_setattr() 2) Return an error in calipso_req_setattr() 3) Alaways set rsk_listener 1) is no go as it bypasses LSM, but 2) effectively disables SYN Cookie for CALIPSO. 3) is also no go as there have been many efforts to reduce atomic ops and make TCP robust against DDoS. See also commit 3b24d85 ("tcp/dccp: do not touch listener sk_refcnt under synflood"). As of the blamed commit, SYN Cookie already did not need refcounting, and no one has stumbled on the bug for 9 years, so no CALIPSO user will care about SYN Cookie. Let's return an error in calipso_req_setattr() and calipso_req_delattr() in the SYN Cookie case. This can be reproduced by [1] on Fedora and now connect() of nc times out. [0]: TCP: request_sock_TCPv6: Possible SYN flooding on port [::]:20002. Sending cookies. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] CPU: 3 UID: 0 PID: 12262 Comm: syz.1.2611 Not tainted 6.14.0 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:read_pnet include/net/net_namespace.h:406 [inline] RIP: 0010:sock_net include/net/sock.h:655 [inline] RIP: 0010:sock_kmalloc+0x35/0x170 net/core/sock.c:2806 Code: 89 d5 41 54 55 89 f5 53 48 89 fb e8 25 e3 c6 fd e8 f0 91 e3 00 48 8d 7b 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 26 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b RSP: 0018:ffff88811af89038 EFLAGS: 00010216 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff888105266400 RDX: 0000000000000006 RSI: ffff88800c890000 RDI: 0000000000000030 RBP: 0000000000000050 R08: 0000000000000000 R09: ffff88810526640e R10: ffffed1020a4cc81 R11: ffff88810526640f R12: 0000000000000000 R13: 0000000000000820 R14: ffff888105266400 R15: 0000000000000050 FS: 00007f0653a07640(0000) GS:ffff88811af80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f863ba096f4 CR3: 00000000163c0005 CR4: 0000000000770ef0 PKRU: 80000000 Call Trace: <IRQ> ipv6_renew_options+0x279/0x950 net/ipv6/exthdrs.c:1288 calipso_req_setattr+0x181/0x340 net/ipv6/calipso.c:1204 calipso_req_setattr+0x56/0x80 net/netlabel/netlabel_calipso.c:597 netlbl_req_setattr+0x18a/0x440 net/netlabel/netlabel_kapi.c:1249 selinux_netlbl_inet_conn_request+0x1fb/0x320 security/selinux/netlabel.c:342 selinux_inet_conn_request+0x1eb/0x2c0 security/selinux/hooks.c:5551 security_inet_conn_request+0x50/0xa0 security/security.c:4945 tcp_v6_route_req+0x22c/0x550 net/ipv6/tcp_ipv6.c:825 tcp_conn_request+0xec8/0x2b70 net/ipv4/tcp_input.c:7275 tcp_v6_conn_request+0x1e3/0x440 net/ipv6/tcp_ipv6.c:1328 tcp_rcv_state_process+0xafa/0x52b0 net/ipv4/tcp_input.c:6781 tcp_v6_do_rcv+0x8a6/0x1a40 net/ipv6/tcp_ipv6.c:1667 tcp_v6_rcv+0x505e/0x5b50 net/ipv6/tcp_ipv6.c:1904 ip6_protocol_deliver_rcu+0x17c/0x1da0 net/ipv6/ip6_input.c:436 ip6_input_finish+0x103/0x180 net/ipv6/ip6_input.c:480 NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip6_input+0x13c/0x6b0 net/ipv6/ip6_input.c:491 dst_input include/net/dst.h:469 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] ip6_rcv_finish+0xb6/0x490 net/ipv6/ip6_input.c:69 NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ipv6_rcv+0xf9/0x490 net/ipv6/ip6_input.c:309 __netif_receive_skb_one_core+0x12e/0x1f0 net/core/dev.c:5896 __netif_receive_skb+0x1d/0x170 net/core/dev.c:6009 process_backlog+0x41e/0x13b0 net/core/dev.c:6357 __napi_poll+0xbd/0x710 net/core/dev.c:7191 napi_poll net/core/dev.c:7260 [inline] net_rx_action+0x9de/0xde0 net/core/dev.c:7382 handle_softirqs+0x19a/0x770 kernel/softirq.c:561 do_softirq.part.0+0x36/0x70 kernel/softirq.c:462 </IRQ> <TASK> do_softirq arch/x86/include/asm/preempt.h:26 [inline] __local_bh_enable_ip+0xf1/0x110 kernel/softirq.c:389 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] __dev_queue_xmit+0xc2a/0x3c40 net/core/dev.c:4679 dev_queue_xmit include/linux/netdevice.h:3313 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip6_finish_output2+0xd69/0x1f80 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x5dc/0xd60 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x24b/0x8d0 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip6_xmit+0xbbc/0x20d0 net/ipv6/ip6_output.c:366 inet6_csk_xmit+0x39a/0x720 net/ipv6/inet6_connection_sock.c:135 __tcp_transmit_skb+0x1a7b/0x3b40 net/ipv4/tcp_output.c:1471 tcp_transmit_skb net/ipv4/tcp_output.c:1489 [inline] tcp_send_syn_data net/ipv4/tcp_output.c:4059 [inline] tcp_connect+0x1c0c/0x4510 net/ipv4/tcp_output.c:4148 tcp_v6_connect+0x156c/0x2080 net/ipv6/tcp_ipv6.c:333 __inet_stream_connect+0x3a7/0xed0 net/ipv4/af_inet.c:677 tcp_sendmsg_fastopen+0x3e2/0x710 net/ipv4/tcp.c:1039 tcp_sendmsg_locked+0x1e82/0x3570 net/ipv4/tcp.c:1091 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1358 inet6_sendmsg+0xb9/0x150 net/ipv6/af_inet6.c:659 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0xf4/0x2a0 net/socket.c:733 __sys_sendto+0x29a/0x390 net/socket.c:2187 __do_sys_sendto net/socket.c:2194 [inline] __se_sys_sendto net/socket.c:2190 [inline] __x64_sys_sendto+0xe1/0x1c0 net/socket.c:2190 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc3/0x1d0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f06553c47ed Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0653a06fc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f0655605fa0 RCX: 00007f06553c47ed RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000b RBP: 00007f065545db38 R08: 0000200000000140 R09: 000000000000001c R10: f7384d4ea84b01bd R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0655605fac R14: 00007f0655606038 R15: 00007f06539e7000 </TASK> Modules linked in: [1]: dnf install -y selinux-policy-targeted policycoreutils netlabel_tools procps-ng nmap-ncat mount -t selinuxfs none /sys/fs/selinux load_policy netlabelctl calipso add pass doi:1 netlabelctl map del default netlabelctl map add default address:::1 protocol:calipso,1 sysctl net.ipv4.tcp_syncookies=2 nc -l ::1 80 & nc ::1 80 Fixes: e1adea9 ("calipso: Allow request sockets to be relabelled by the lsm.") Reported-by: syzkaller <syzkaller@googlegroups.com> Reported-by: John Cheung <john.cs.hey@gmail.com> Closes: https://lore.kernel.org/netdev/CAP=Rh=MvfhrGADy+-WJiftV2_WzMH4VEhEFmeT28qY+4yxNu4w@mail.gmail.com/ Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://patch.msgid.link/20250617224125.17299-1-kuni1840@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The WARN_ON_ONCE is introduced on truncate_folio_batch_exceptionals() to capture whether the filesystem has removed all DAX entries or not. And the fix has been applied on the filesystem xfs and ext4 by the commit 0e2f80a ("fs/dax: ensure all pages are idle prior to filesystem unmount"). Apply the missed fix on filesystem fuse to fix the runtime warning: [ 2.011450] ------------[ cut here ]------------ [ 2.011873] WARNING: CPU: 0 PID: 145 at mm/truncate.c:89 truncate_folio_batch_exceptionals+0x272/0x2b0 [ 2.012468] Modules linked in: [ 2.012718] CPU: 0 UID: 1000 PID: 145 Comm: weston Not tainted 6.16.0-rc2-WSL2-STABLE #2 PREEMPT(undef) [ 2.013292] RIP: 0010:truncate_folio_batch_exceptionals+0x272/0x2b0 [ 2.013704] Code: 48 63 d0 41 29 c5 48 8d 1c d5 00 00 00 00 4e 8d 6c 2a 01 49 c1 e5 03 eb 09 48 83 c3 08 49 39 dd 74 83 41 f6 44 1c 08 01 74 ef <0f> 0b 49 8b 34 1e 48 89 ef e8 10 a2 17 00 eb df 48 8b 7d 00 e8 35 [ 2.014845] RSP: 0018:ffffa47ec33f3b10 EFLAGS: 00010202 [ 2.015279] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 2.015884] RDX: 0000000000000000 RSI: ffffa47ec33f3ca0 RDI: ffff98aa44f3fa80 [ 2.016377] RBP: ffff98aa44f3fbf0 R08: ffffa47ec33f3ba8 R09: 0000000000000000 [ 2.016942] R10: 0000000000000001 R11: 0000000000000000 R12: ffffa47ec33f3ca0 [ 2.017437] R13: 0000000000000008 R14: ffffa47ec33f3ba8 R15: 0000000000000000 [ 2.017972] FS: 000079ce006afa40(0000) GS:ffff98aade441000(0000) knlGS:0000000000000000 [ 2.018510] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2.018987] CR2: 000079ce03e74000 CR3: 000000010784f006 CR4: 0000000000372eb0 [ 2.019518] Call Trace: [ 2.019729] <TASK> [ 2.019901] truncate_inode_pages_range+0xd8/0x400 [ 2.020280] ? timerqueue_add+0x66/0xb0 [ 2.020574] ? get_nohz_timer_target+0x2a/0x140 [ 2.020904] ? timerqueue_add+0x66/0xb0 [ 2.021231] ? timerqueue_del+0x2e/0x50 [ 2.021646] ? __remove_hrtimer+0x39/0x90 [ 2.022017] ? srso_alias_untrain_ret+0x1/0x10 [ 2.022497] ? psi_group_change+0x136/0x350 [ 2.023046] ? _raw_spin_unlock+0xe/0x30 [ 2.023514] ? finish_task_switch.isra.0+0x8d/0x280 [ 2.024068] ? __schedule+0x532/0xbd0 [ 2.024551] fuse_evict_inode+0x29/0x190 [ 2.025131] evict+0x100/0x270 [ 2.025641] ? _atomic_dec_and_lock+0x39/0x50 [ 2.026316] ? __pfx_generic_delete_inode+0x10/0x10 [ 2.026843] __dentry_kill+0x71/0x180 [ 2.027335] dput+0xeb/0x1b0 [ 2.027725] __fput+0x136/0x2b0 [ 2.028054] __x64_sys_close+0x3d/0x80 [ 2.028469] do_syscall_64+0x6d/0x1b0 [ 2.028832] ? clear_bhb_loop+0x30/0x80 [ 2.029182] ? clear_bhb_loop+0x30/0x80 [ 2.029533] ? clear_bhb_loop+0x30/0x80 [ 2.029902] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 2.030423] RIP: 0033:0x79ce03d0d067 [ 2.030820] Code: b8 ff ff ff ff e9 3e ff ff ff 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 a7 f8 ff [ 2.032354] RSP: 002b:00007ffef0498948 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 2.032939] RAX: ffffffffffffffda RBX: 00007ffef0498960 RCX: 000079ce03d0d067 [ 2.033612] RDX: 0000000000000003 RSI: 0000000000001000 RDI: 000000000000000d [ 2.034289] RBP: 00007ffef0498a30 R08: 000000000000000d R09: 0000000000000000 [ 2.034944] R10: 00007ffef0498978 R11: 0000000000000246 R12: 0000000000000001 [ 2.035610] R13: 00007ffef0498960 R14: 000079ce03e09ce0 R15: 0000000000000003 [ 2.036301] </TASK> [ 2.036532] ---[ end trace 0000000000000000 ]--- Link: https://lkml.kernel.org/r/20250621171507.3770-1-haiyuewa@163.com Fixes: bde708f ("fs/dax: always remove DAX page-cache entries when breaking layouts") Signed-off-by: Haiyue Wang <haiyuewa@163.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Fix cifs_signal_cifsd_for_reconnect() to take the correct lock order and prevent the following deadlock from happening ====================================================== WARNING: possible circular locking dependency detected 6.16.0-rc3-build2+ #1301 Tainted: G S W ------------------------------------------------------ cifsd/6055 is trying to acquire lock: ffff88810ad56038 (&tcp_ses->srv_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0x134/0x200 but task is already holding lock: ffff888119c64330 (&ret_buf->chan_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0xcf/0x200 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&ret_buf->chan_lock){+.+.}-{3:3}: validate_chain+0x1cf/0x270 __lock_acquire+0x60e/0x780 lock_acquire.part.0+0xb4/0x1f0 _raw_spin_lock+0x2f/0x40 cifs_setup_session+0x81/0x4b0 cifs_get_smb_ses+0x771/0x900 cifs_mount_get_session+0x7e/0x170 cifs_mount+0x92/0x2d0 cifs_smb3_do_mount+0x161/0x460 smb3_get_tree+0x55/0x90 vfs_get_tree+0x46/0x180 do_new_mount+0x1b0/0x2e0 path_mount+0x6ee/0x740 do_mount+0x98/0xe0 __do_sys_mount+0x148/0x180 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #1 (&ret_buf->ses_lock){+.+.}-{3:3}: validate_chain+0x1cf/0x270 __lock_acquire+0x60e/0x780 lock_acquire.part.0+0xb4/0x1f0 _raw_spin_lock+0x2f/0x40 cifs_match_super+0x101/0x320 sget+0xab/0x270 cifs_smb3_do_mount+0x1e0/0x460 smb3_get_tree+0x55/0x90 vfs_get_tree+0x46/0x180 do_new_mount+0x1b0/0x2e0 path_mount+0x6ee/0x740 do_mount+0x98/0xe0 __do_sys_mount+0x148/0x180 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #0 (&tcp_ses->srv_lock){+.+.}-{3:3}: check_noncircular+0x95/0xc0 check_prev_add+0x115/0x2f0 validate_chain+0x1cf/0x270 __lock_acquire+0x60e/0x780 lock_acquire.part.0+0xb4/0x1f0 _raw_spin_lock+0x2f/0x40 cifs_signal_cifsd_for_reconnect+0x134/0x200 __cifs_reconnect+0x8f/0x500 cifs_handle_standard+0x112/0x280 cifs_demultiplex_thread+0x64d/0xbc0 kthread+0x2f7/0x310 ret_from_fork+0x2a/0x230 ret_from_fork_asm+0x1a/0x30 other info that might help us debug this: Chain exists of: &tcp_ses->srv_lock --> &ret_buf->ses_lock --> &ret_buf->chan_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ret_buf->chan_lock); lock(&ret_buf->ses_lock); lock(&ret_buf->chan_lock); lock(&tcp_ses->srv_lock); *** DEADLOCK *** 3 locks held by cifsd/6055: #0: ffffffff857de398 (&cifs_tcp_ses_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0x7b/0x200 #1: ffff888119c64060 (&ret_buf->ses_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0x9c/0x200 #2: ffff888119c64330 (&ret_buf->chan_lock){+.+.}-{3:3}, at: cifs_signal_cifsd_for_reconnect+0xcf/0x200 Cc: linux-cifs@vger.kernel.org Reported-by: David Howells <dhowells@redhat.com> Fixes: d7d7a66 ("cifs: avoid use of global locks for high contention data") Reviewed-by: David Howells <dhowells@redhat.com> Tested-by: David Howells <dhowells@redhat.com> Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>

Example of using function casting

201627f

More info https://stackoverflow.com/questions/559581/casting-a-function-pointer-to-another-type/14044244#14044244

rlmenge closed this Oct 5, 2023

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Example of using function casting#2

Example of using function casting#2
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rlmenge commented Sep 20, 2023

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