pm24.git/kernel, branch rust-6.5

Merge tag 'core-debugobjects-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-05-28T11:15:33Z

Pull debugobjects fixes from Thomas Gleixner: "Two fixes for debugobjects: - Prevent the allocation path from waking up kswapd. That's a long standing issue due to the GFP_ATOMIC allocation flag. As debug objects can be invoked from pretty much any context waking kswapd can end up in arbitrary lock chains versus the waitqueue lock - Correct the explicit lockdep wait-type violation in debug_object_fill_pool()" * tag 'core-debugobjects-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: debugobjects: Don't wake up kswapd from fill_pool() debugobjects,locking: Annotate debug_object_fill_pool() wait type violation

Merge tag 'for-linus-6.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2023-05-27T16:42:56Z

Pull xen fixes from Juergen Gross: - a double free fix in the Xen pvcalls backend driver - a fix for a regression causing the MSI related sysfs entries to not being created in Xen PV guests - a fix in the Xen blkfront driver for handling insane input data better * tag 'for-linus-6.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: x86/pci/xen: populate MSI sysfs entries xen/pvcalls-back: fix double frees with pvcalls_new_active_socket() xen/blkfront: Only check REQ_FUA for writes

module: error out early on concurrent load of the same module file

2023-05-26T00:07:57Z

It turns out that udev under certain circumstances will concurrently try to load the same modules over-and-over excessively. This isn't a kernel bug, but it ends up affecting the kernel, to the point that under certain circumstances we can fail to boot, because the kernel uses a lot of memory to read all the module data all at once. Note that it isn't a memory leak, it's just basically a thundering herd problem happening at bootup with a lot of CPUs, with the worst cases then being pretty bad. Admittedly the worst situations are somewhat contrived: lots and lots of CPUs, not a lot of memory, and KASAN enabled to make it all slower and as such (unintentionally) exacerbate the problem. Luis explains: [1] "My best assessment of the situation is that each CPU in udev ends up triggering a load of duplicate set of modules, not just one, but *a lot*. Not sure what heuristics udev uses to load a set of modules per CPU." Petr Pavlu chimes in: [2] "My understanding is that udev workers are forked. An initial kmod context is created by the main udevd process but no sharing happens after the fork. It means that the mentioned memory pool logic doesn't really kick in. Multiple parallel load requests come from multiple udev workers, for instance, each handling an udev event for one CPU device and making the exactly same requests as all others are doing at the same time. The optimization idea would be to recognize these duplicate requests at the udevd/kmod level and converge them" Note that module loading has tried to mitigate this issue before, see for example commit 064f4536d139 ("module: avoid allocation if module is already present and ready"), which has a few ASCII graphs on memory use due to this same issue. However, while that noticed that the module was already loaded, and exited with an error early before spending any more time on setting up the module, it didn't handle the case of multiple concurrent module loads all being active - but not complete - at the same time. Yes, one of them will eventually win the race and finalize its copy, and the others will then notice that the module already exists and error out, but while this all happens, we have tons of unnecessary concurrent work being done. Again, the real fix is for udev to not do that (maybe it should use threads instead of fork, and have actual shared data structures and not cause duplicate work). That real fix is apparently not trivial. But it turns out that the kernel already has a pretty good model for dealing with concurrent access to the same file: the i_writecount of the inode. In fact, the module loading already indirectly uses 'i_writecount' , because 'kernel_file_read()' will in fact do ret = deny_write_access(file); if (ret) return ret; ... allow_write_access(file); around the read of the file data. We do not allow concurrent writes to the file, and return -ETXTBUSY if the file was open for writing at the same time as the module data is loaded from it. And the solution to the reader concurrency problem is to simply extend this "no concurrent writers" logic to simply be "exclusive access". Note that "exclusive" in this context isn't really some absolute thing: it's only exclusion from writers and from other "special readers" that do this writer denial. So we simply introduce a variation of that "deny_write_access()" logic that not only denies write access, but also requires that this is the _only_ such access that denies write access. Which means that you can't start loading a module that is already being loaded as a module by somebody else, or you will get the same -ETXTBSY error that you would get if there were writers around. [ It also means that you can't try to load a currently executing executable as a module, for the same reason: executables do that same "deny_write_access()" thing, and that's obviously where the whole ETXTBSY logic traditionally came from. This is not a problem for kernel modules, since the set of normal executable files and kernel module files is entirely disjoint. ] This new function is called "exclusive_deny_write_access()", and the implementation is trivial, in that it's just an atomic decrement of i_writecount if it was 0 before. To use that new exclusivity check, all we then do is wrap the module loading with that exclusive_deny_write_access()() / allow_write_access() pair. The actual patch is a bit bigger than that, because we want to surround not just the "load file data" part, but the whole module setup, to get maximum exclusion. So this ends up splitting up "finit_module()" into a few helper functions to make it all very clear and legible. In Luis' test-case (bringing up 255 vcpu's in a virtual machine [3]), the "wasted vmalloc" space (ie module data read into a vmalloc'ed area in order to be loaded as a module, but then discarded because somebody else loaded the same module instead) dropped from 1.8GiB to 474kB. Yes, that's gigabytes to kilobytes. It doesn't drop completely to zero, because even with this change, you can still end up having completely serial pointless module loads, where one udev process has loaded a module fully (and thus the kernel has released that exclusive lock on the module file), and then another udev process tries to load the same module again. So while we cannot fully get rid of the fundamental bug in user space, we _can_ get rid of the excessive concurrent thundering herd effect. A couple of final side notes on this all: - This tweak only affects the "finit_module()" system call, which gives the kernel a file descriptor with the module data. You can also just feed the module data as raw data from user space with "init_module()" (note the lack of 'f' at the beginning), and obviously for that case we do _not_ have any "exclusive read" logic. So if you absolutely want to do things wrong in user space, and try to load the same module multiple times, and error out only later when the kernel ends up saying "you can't load the same module name twice", you can still do that. And in fact, some distros will do exactly that, because they will uncompress the kernel module data in user space before feeding it to the kernel (mainly because they haven't started using the new kernel side decompression yet). So this is not some absolute "you can't do concurrent loads of the same module". It's literally just a very simple heuristic that will catch it early in case you try to load the exact same module file at the same time, and in that case avoid a potentially nasty situation. - There is another user of "deny_write_access()": the verity code that enables fs-verity on a file (the FS_IOC_ENABLE_VERITY ioctl). If you use fs-verity and you care about verifying the kernel modules (which does make sense), you should do it *before* loading said kernel module. That may sound obvious, but now the implementation basically requires it. Because if you try to do it concurrently, the kernel may refuse to load the module file that is being set up by the fs-verity code. - This all will obviously mean that if you insist on loading the same module in parallel, only one module load will succeed, and the others will return with an error. That was true before too, but what is different is that the -ETXTBSY error can be returned *before* the success case of another process fully loading and instantiating the module. Again, that might sound obvious, and it is indeed the whole point of the whole change: we are much quicker to notice the whole "you're already in the process of loading this module". So it's very much intentional, but it does mean that if you just spray the kernel with "finit_module()", and expect that the module is immediately loaded afterwards without checking the return value, you are doing something horribly horribly wrong. I'd like to say that that would never happen, but the whole _reason_ for this commit is that udev is currently doing something horribly horribly wrong, so ... Link: https://lore.kernel.org/all/ZEGopJ8VAYnE7LQ2@bombadil.infradead.org/ [1] Link: https://lore.kernel.org/all/23bd0ce6-ef78-1cd8-1f21-0e706a00424a@suse.com/ [2] Link: https://lore.kernel.org/lkml/ZG%2Fa+nrt4%2FAAUi5z@bombadil.infradead.org/ [3] Cc: Greg Kroah-Hartman Cc: Lucas De Marchi Cc: Petr Pavlu Tested-by: Luis Chamberlain Signed-off-by: Linus Torvalds

Merge tag 'net-6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2023-05-25T17:55:26Z

Pull networking fixes from Paolo Abeni: "Including fixes from bluetooth and bpf. Current release - regressions: - net: fix skb leak in __skb_tstamp_tx() - eth: mtk_eth_soc: fix QoS on DSA MAC on non MTK_NETSYS_V2 SoCs Current release - new code bugs: - handshake: - fix sock->file allocation - fix handshake_dup() ref counting - bluetooth: - fix potential double free caused by hci_conn_unlink - fix UAF in hci_conn_hash_flush Previous releases - regressions: - core: fix stack overflow when LRO is disabled for virtual interfaces - tls: fix strparser rx issues - bpf: - fix many sockmap/TCP related issues - fix a memory leak in the LRU and LRU_PERCPU hash maps - init the offload table earlier - eth: mlx5e: - do as little as possible in napi poll when budget is 0 - fix using eswitch mapping in nic mode - fix deadlock in tc route query code Previous releases - always broken: - udplite: fix NULL pointer dereference in __sk_mem_raise_allocated() - raw: fix output xfrm lookup wrt protocol - smc: reset connection when trying to use SMCRv2 fails - phy: mscc: enable VSC8501/2 RGMII RX clock - eth: octeontx2-pf: fix TSOv6 offload - eth: cdc_ncm: deal with too low values of dwNtbOutMaxSize" * tag 'net-6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (79 commits) udplite: Fix NULL pointer dereference in __sk_mem_raise_allocated(). net: phy: mscc: enable VSC8501/2 RGMII RX clock net: phy: mscc: remove unnecessary phydev locking net: phy: mscc: add support for VSC8501 net: phy: mscc: add VSC8502 to MODULE_DEVICE_TABLE net/handshake: Enable the SNI extension to work properly net/handshake: Unpin sock->file if a handshake is cancelled net/handshake: handshake_genl_notify() shouldn't ignore @flags net/handshake: Fix uninitialized local variable net/handshake: Fix handshake_dup() ref counting net/handshake: Remove unneeded check from handshake_dup() ipv6: Fix out-of-bounds access in ipv6_find_tlv() net: ethernet: mtk_eth_soc: fix QoS on DSA MAC on non MTK_NETSYS_V2 SoCs docs: netdev: document the existence of the mail bot net: fix skb leak in __skb_tstamp_tx() r8169: Use a raw_spinlock_t for the register locks. page_pool: fix inconsistency for page_pool_ring_[un]lock() bpf, sockmap: Test progs verifier error with latest clang bpf, sockmap: Test FIONREAD returns correct bytes in rx buffer with drops bpf, sockmap: Test FIONREAD returns correct bytes in rx buffer ...

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2023-05-25T04:57:57Z

Daniel Borkmann says: ==================== pull-request: bpf 2023-05-24 We've added 19 non-merge commits during the last 10 day(s) which contain a total of 20 files changed, 738 insertions(+), 448 deletions(-). The main changes are: 1) Batch of BPF sockmap fixes found when running against NGINX TCP tests, from John Fastabend. 2) Fix a memleak in the LRU{,_PERCPU} hash map when bucket locking fails, from Anton Protopopov. 3) Init the BPF offload table earlier than just late_initcall, from Jakub Kicinski. 4) Fix ctx access mask generation for 32-bit narrow loads of 64-bit fields, from Will Deacon. 5) Remove a now unsupported __fallthrough in BPF samples, from Andrii Nakryiko. 6) Fix a typo in pkg-config call for building sign-file, from Jeremy Sowden. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: bpf, sockmap: Test progs verifier error with latest clang bpf, sockmap: Test FIONREAD returns correct bytes in rx buffer with drops bpf, sockmap: Test FIONREAD returns correct bytes in rx buffer bpf, sockmap: Test shutdown() correctly exits epoll and recv()=0 bpf, sockmap: Build helper to create connected socket pair bpf, sockmap: Pull socket helpers out of listen test for general use bpf, sockmap: Incorrectly handling copied_seq bpf, sockmap: Wake up polling after data copy bpf, sockmap: TCP data stall on recv before accept bpf, sockmap: Handle fin correctly bpf, sockmap: Improved check for empty queue bpf, sockmap: Reschedule is now done through backlog bpf, sockmap: Convert schedule_work into delayed_work bpf, sockmap: Pass skb ownership through read_skb bpf: fix a memory leak in the LRU and LRU_PERCPU hash maps bpf: Fix mask generation for 32-bit narrow loads of 64-bit fields samples/bpf: Drop unnecessary fallthrough bpf: netdev: init the offload table earlier selftests/bpf: Fix pkg-config call building sign-file ==================== Link: https://lore.kernel.org/r/20230524170839.13905-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski

x86/pci/xen: populate MSI sysfs entries

2023-05-24T16:08:49Z

Commit bf5e758f02fc ("genirq/msi: Simplify sysfs handling") reworked the creation of sysfs entries for MSI IRQs. The creation used to be in msi_domain_alloc_irqs_descs_locked after calling ops->domain_alloc_irqs. Then it moved into __msi_domain_alloc_irqs which is an implementation of domain_alloc_irqs. However, Xen comes with the only other implementation of domain_alloc_irqs and hence doesn't run the sysfs population code anymore. Commit 6c796996ee70 ("x86/pci/xen: Fixup fallout from the PCI/MSI overhaul") set the flag MSI_FLAG_DEV_SYSFS for the xen msi_domain_info but that doesn't actually have an effect because Xen uses it's own domain_alloc_irqs implementation. Fix this by making use of the fallback functions for sysfs population. Fixes: bf5e758f02fc ("genirq/msi: Simplify sysfs handling") Signed-off-by: Maximilian Heyne Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20230503131656.15928-1-mheyne@amazon.de Signed-off-by: Juergen Gross

module: Fix use-after-free bug in read_file_mod_stats()

2023-05-22T21:13:13Z

Smatch warns: kernel/module/stats.c:394 read_file_mod_stats() warn: passing freed memory 'buf' We are passing 'buf' to simple_read_from_buffer() after freeing it. Fix this by changing the order of 'simple_read_from_buffer' and 'kfree'. Fixes: df3e764d8e5c ("module: add debug stats to help identify memory pressure") Signed-off-by: Harshit Mogalapalli Signed-off-by: Luis Chamberlain

bpf: fix a memory leak in the LRU and LRU_PERCPU hash maps

2023-05-22T17:26:39Z

The LRU and LRU_PERCPU maps allocate a new element on update before locking the target hash table bucket. Right after that the maps try to lock the bucket. If this fails, then maps return -EBUSY to the caller without releasing the allocated element. This makes the element untracked: it doesn't belong to either of free lists, and it doesn't belong to the hash table, so can't be re-used; this eventually leads to the permanent -ENOMEM on LRU map updates, which is unexpected. Fix this by returning the element to the local free list if bucket locking fails. Fixes: 20b6cc34ea74 ("bpf: Avoid hashtab deadlock with map_locked") Signed-off-by: Anton Protopopov Link: https://lore.kernel.org/r/20230522154558.2166815-1-aspsk@isovalent.com Signed-off-by: Martin KaFai Lau

bpf: Fix mask generation for 32-bit narrow loads of 64-bit fields

2023-05-19T16:58:37Z

A narrow load from a 64-bit context field results in a 64-bit load followed potentially by a 64-bit right-shift and then a bitwise AND operation to extract the relevant data. In the case of a 32-bit access, an immediate mask of 0xffffffff is used to construct a 64-bit BPP_AND operation which then sign-extends the mask value and effectively acts as a glorified no-op. For example: 0: 61 10 00 00 00 00 00 00 r0 = *(u32 *)(r1 + 0) results in the following code generation for a 64-bit field: ldr x7, [x7] // 64-bit load mov x10, #0xffffffffffffffff and x7, x7, x10 Fix the mask generation so that narrow loads always perform a 32-bit AND operation: ldr x7, [x7] // 64-bit load mov w10, #0xffffffff and w7, w7, w10 Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: John Fastabend Cc: Krzesimir Nowak Cc: Andrey Ignatov Acked-by: Yonghong Song Fixes: 31fd85816dbe ("bpf: permits narrower load from bpf program context fields") Signed-off-by: Will Deacon Link: https://lore.kernel.org/r/20230518102528.1341-1-will@kernel.org Signed-off-by: Alexei Starovoitov

Merge tag 'probes-fixes-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2023-05-18T16:04:45Z

Pull probes fixes from Masami Hiramatsu: - Initialize 'ret' local variables on fprobe_handler() to fix the smatch warning. With this, fprobe function exit handler is not working randomly. - Fix to use preempt_enable/disable_notrace for rethook handler to prevent recursive call of fprobe exit handler (which is based on rethook) - Fix recursive call issue on fprobe_kprobe_handler() - Fix to detect recursive call on fprobe_exit_handler() - Fix to make all arch-dependent rethook code notrace (the arch-independent code is already notrace)" * tag 'probes-fixes-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: rethook, fprobe: do not trace rethook related functions fprobe: add recursion detection in fprobe_exit_handler fprobe: make fprobe_kprobe_handler recursion free rethook: use preempt_{disable, enable}_notrace in rethook_trampoline_handler tracing: fprobe: Initialize ret valiable to fix smatch error