July 2025 - Linux-stable-mirror

[PATCH v3] fscrypt: Don't use problematic non-inline crypto engines

by Eric Biggers

Make fscrypt no longer use Crypto API drivers for non-inline crypto engines, even when the Crypto API prioritizes them over CPU-based code (which unfortunately it often does). These drivers tend to be really problematic, especially for fscrypt's workload. This commit has no effect on inline crypto engines, which are different and do work well. Specifically, exclude drivers that have CRYPTO_ALG_KERN_DRIVER_ONLY or CRYPTO_ALG_ALLOCATES_MEMORY set. (Later, CRYPTO_ALG_ASYNC should be excluded too. That's omitted for now to keep this commit backportable, since until recently some CPU-based code had CRYPTO_ALG_ASYNC set.) There are two major issues with these drivers: bugs and performance. First, these drivers tend to be buggy. They're fundamentally much more error-prone and harder to test than the CPU-based code. They often don't get tested before kernel releases, and even if they do, the crypto self-tests don't properly test these drivers. Released drivers have en/decrypted or hashed data incorrectly. These bugs cause issues for fscrypt users who often didn't even want to use these drivers, e.g.: - https://github.com/google/fscryptctl/issues/32 - https://github.com/google/fscryptctl/issues/9 - https://lore.kernel.org/r/PH0PR02MB731916ECDB6C613665863B6CFFAA2@PH0PR02MB7… These drivers have also similarly caused issues for dm-crypt users, including data corruption and deadlocks. Since Linux v5.10, dm-crypt has disabled most of them by excluding CRYPTO_ALG_ALLOCATES_MEMORY. Second, these drivers tend to be *much* slower than the CPU-based code. This may seem counterintuitive, but benchmarks clearly show it. There's a *lot* of overhead associated with going to a hardware driver, off the CPU, and back again. To prove this, I gathered as many systems with this type of crypto engine as I could, and I measured synchronous encryption of 4096-byte messages (which matches fscrypt's workload): Intel Emerald Rapids server: AES-256-XTS: xts-aes-vaes-avx512 16171 MB/s [CPU-based, Vector AES] qat_aes_xts 289 MB/s [Offload, Intel QuickAssist] Qualcomm SM8650 HDK: AES-256-XTS: xts-aes-ce 4301 MB/s [CPU-based, ARMv8 Crypto Extensions] xts-aes-qce 73 MB/s [Offload, Qualcomm Crypto Engine] i.MX 8M Nano LPDDR4 EVK: AES-256-XTS: xts-aes-ce 647 MB/s [CPU-based, ARMv8 Crypto Extensions] xts(ecb-aes-caam) 20 MB/s [Offload, CAAM] AES-128-CBC-ESSIV: essiv(cbc-aes-caam,sha256-lib) 23 MB/s [Offload, CAAM] STM32MP157F-DK2: AES-256-XTS: xts-aes-neonbs 13.2 MB/s [CPU-based, ARM NEON] xts(stm32-ecb-aes) 3.1 MB/s [Offload, STM32 crypto engine] AES-128-CBC-ESSIV: essiv(cbc-aes-neonbs,sha256-lib) 14.7 MB/s [CPU-based, ARM NEON] essiv(stm32-cbc-aes,sha256-lib) 3.2 MB/s [Offload, STM32 crypto engine] Adiantum: adiantum(xchacha12-arm,aes-arm,nhpoly1305-neon) 52.8 MB/s [CPU-based, ARM scalar + NEON] So, there was no case in which the crypto engine was even *close* to being faster. On the first three, which have AES instructions in the CPU, the CPU was 30 to 55 times faster (!). Even on STM32MP157F-DK2 which has a Cortex-A7 CPU that doesn't have AES instructions, AES was over 4 times faster on the CPU. And Adiantum encryption, which is what actually should be used on CPUs like that, was over 17 times faster. Other justifications that have been given for these non-inline crypto engines (almost always coming from the hardware vendors, not actual users) don't seem very plausible either: - The crypto engine throughput could be improved by processing multiple requests concurrently. Currently irrelevant to fscrypt, since it doesn't do that. This would also be complex, and unhelpful in many cases. 2 of the 4 engines I tested even had only one queue. - Some of the engines, e.g. STM32, support hardware keys. Also currently irrelevant to fscrypt, since it doesn't support these. Interestingly, the STM32 driver itself doesn't support this either. - Free up CPU for other tasks and/or reduce energy usage. Not very plausible considering the "short" message length, driver overhead, and scheduling overhead. There's just very little time for the CPU to do something else like run another task or enter low-power state, before the message finishes and it's time to process the next one. - Some of these engines resist power analysis and electromagnetic attacks, while the CPU-based crypto generally does not. In theory, this sounds great. In practice, if this benefit requires the use of an off-CPU offload that massively regresses performance and has a low-quality, buggy driver, the price for this hardening (which is not relevant to most fscrypt users, and tends to be incomplete) is just too high. Inline crypto engines are much more promising here, as are on-CPU solutions like RISC-V High Assurance Cryptography. Fixes: b30ab0e03407 ("ext4 crypto: add ext4 encryption facilities") Cc: stable(a)vger.kernel.org Signed-off-by: Eric Biggers <ebiggers(a)kernel.org> --- Changed in v3: - Further improved the commit message and comment. Added data for STM32MP157F-DK2 and i.MX 8M Nano LPDDR4 EVK. - Updated fscrypt.rst Changed in v2: - Improved commit message and comment - Dropped CRYPTO_ALG_ASYNC from the mask, to make this patch backport-friendly - Added Fixes and Cc stable Documentation/filesystems/fscrypt.rst | 37 +++++++++++---------------- fs/crypto/fscrypt_private.h | 17 ++++++++++++ fs/crypto/hkdf.c | 2 +- fs/crypto/keysetup.c | 3 ++- fs/crypto/keysetup_v1.c | 3 ++- 5 files changed, 37 insertions(+), 25 deletions(-) diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 29e84d125e02..4a3e844b790c 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -145,13 +145,12 @@ However, these ioctls have some limitations: caches are freed but not wiped. Therefore, portions thereof may be recoverable from freed memory, even after the corresponding key(s) were wiped. To partially solve this, you can add init_on_free=1 to your kernel command line. However, this has a performance cost. -- Secret keys might still exist in CPU registers, in crypto - accelerator hardware (if used by the crypto API to implement any of - the algorithms), or in other places not explicitly considered here. +- Secret keys might still exist in CPU registers or in other places + not explicitly considered here. Full system compromise ~~~~~~~~~~~~~~~~~~~~~~ An attacker who gains "root" access and/or the ability to execute @@ -404,13 +403,16 @@ of hardware acceleration for AES. Adiantum is a wide-block cipher that uses XChaCha12 and AES-256 as its underlying components. Most of the work is done by XChaCha12, which is much faster than AES when AES acceleration is unavailable. For more information about Adiantum, see `the Adiantum paper <https://eprint.iacr.org/2018/720.pdf>`_. -The (AES-128-CBC-ESSIV, AES-128-CBC-CTS) pair exists only to support -systems whose only form of AES acceleration is an off-CPU crypto -accelerator such as CAAM or CESA that does not support XTS. +The (AES-128-CBC-ESSIV, AES-128-CBC-CTS) pair was added to try to +provide a more efficient option for systems that lack AES instructions +in the CPU but do have a non-inline crypto engine such as CAAM or CESA +that supports AES-CBC (and not AES-XTS). This is deprecated. It has +been shown that just doing AES on the CPU is actually faster. +Moreover, Adiantum is faster still and is recommended on such systems. The remaining mode pairs are the "national pride ciphers": - (SM4-XTS, SM4-CBC-CTS) @@ -1324,26 +1326,17 @@ that systems implementing a form of "verified boot" take advantage of this by validating all top-level encryption policies prior to access. Inline encryption support ========================= -By default, fscrypt uses the kernel crypto API for all cryptographic -operations (other than HKDF, which fscrypt partially implements -itself). The kernel crypto API supports hardware crypto accelerators, -but only ones that work in the traditional way where all inputs and -outputs (e.g. plaintexts and ciphertexts) are in memory. fscrypt can -take advantage of such hardware, but the traditional acceleration -model isn't particularly efficient and fscrypt hasn't been optimized -for it. - -Instead, many newer systems (especially mobile SoCs) have *inline -encryption hardware* that can encrypt/decrypt data while it is on its -way to/from the storage device. Linux supports inline encryption -through a set of extensions to the block layer called *blk-crypto*. -blk-crypto allows filesystems to attach encryption contexts to bios -(I/O requests) to specify how the data will be encrypted or decrypted -in-line. For more information about blk-crypto, see +Many newer systems (especially mobile SoCs) have *inline encryption +hardware* that can encrypt/decrypt data while it is on its way to/from +the storage device. Linux supports inline encryption through a set of +extensions to the block layer called *blk-crypto*. blk-crypto allows +filesystems to attach encryption contexts to bios (I/O requests) to +specify how the data will be encrypted or decrypted in-line. For more +information about blk-crypto, see :ref:`Documentation/block/inline-encryption.rst <inline_encryption>`. On supported filesystems (currently ext4 and f2fs), fscrypt can use blk-crypto instead of the kernel crypto API to encrypt/decrypt file contents. To enable this, set CONFIG_FS_ENCRYPTION_INLINE_CRYPT=y in diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index c1d92074b65c..6e7164530a1e 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -43,10 +43,27 @@ * hardware-wrapped keys has made it misleading as it's only for raw keys. * Don't use it in kernel code; use one of the above constants instead. */ #undef FSCRYPT_MAX_KEY_SIZE +/* + * This mask is passed as the third argument to the crypto_alloc_*() functions + * to prevent fscrypt from using the Crypto API drivers for non-inline crypto + * engines. Those drivers have been problematic for fscrypt. fscrypt users + * have reported hangs and even incorrect en/decryption with these drivers. + * Since going to the driver, off CPU, and back again is really slow, such + * drivers can be over 50 times slower than the CPU-based code for fscrypt's + * workload. Even on platforms that lack AES instructions on the CPU, using the + * offloads has been shown to be slower, even staying with AES. (Of course, + * Adiantum is faster still, and is the recommended option on such platforms...) + * + * Note that fscrypt also supports inline crypto engines. Those don't use the + * Crypto API and work much better than the old-style (non-inline) engines. + */ +#define FSCRYPT_CRYPTOAPI_MASK \ + (CRYPTO_ALG_ALLOCATES_MEMORY | CRYPTO_ALG_KERN_DRIVER_ONLY) + #define FSCRYPT_CONTEXT_V1 1 #define FSCRYPT_CONTEXT_V2 2 /* Keep this in sync with include/uapi/linux/fscrypt.h */ #define FSCRYPT_MODE_MAX FSCRYPT_MODE_AES_256_HCTR2 diff --git a/fs/crypto/hkdf.c b/fs/crypto/hkdf.c index 0f3028adc9c7..5b9c21cfe2b4 100644 --- a/fs/crypto/hkdf.c +++ b/fs/crypto/hkdf.c @@ -56,11 +56,11 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, struct crypto_shash *hmac_tfm; static const u8 default_salt[HKDF_HASHLEN]; u8 prk[HKDF_HASHLEN]; int err; - hmac_tfm = crypto_alloc_shash(HKDF_HMAC_ALG, 0, 0); + hmac_tfm = crypto_alloc_shash(HKDF_HMAC_ALG, 0, FSCRYPT_CRYPTOAPI_MASK); if (IS_ERR(hmac_tfm)) { fscrypt_err(NULL, "Error allocating " HKDF_HMAC_ALG ": %ld", PTR_ERR(hmac_tfm)); return PTR_ERR(hmac_tfm); } diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 0d71843af946..d8113a719697 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -101,11 +101,12 @@ fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key, const struct inode *inode) { struct crypto_skcipher *tfm; int err; - tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0); + tfm = crypto_alloc_skcipher(mode->cipher_str, 0, + FSCRYPT_CRYPTOAPI_MASK); if (IS_ERR(tfm)) { if (PTR_ERR(tfm) == -ENOENT) { fscrypt_warn(inode, "Missing crypto API support for %s (API name: \"%s\")", mode->friendly_name, mode->cipher_str); diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index b70521c55132..158ceae8a5bc 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -50,11 +50,12 @@ static int derive_key_aes(const u8 *master_key, { int res = 0; struct skcipher_request *req = NULL; DECLARE_CRYPTO_WAIT(wait); struct scatterlist src_sg, dst_sg; - struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0); + struct crypto_skcipher *tfm = + crypto_alloc_skcipher("ecb(aes)", 0, FSCRYPT_CRYPTOAPI_MASK); if (IS_ERR(tfm)) { res = PTR_ERR(tfm); tfm = NULL; goto out; base-commit: d0b3b7b22dfa1f4b515fd3a295b3fd958f9e81af -- 2.50.0

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[PATCH] comedi: Fail COMEDI_INSNLIST ioctl if n_insns is too large

by Ian Abbott

The handling of the `COMEDI_INSNLIST` ioctl allocates a kernel buffer to hold the array of `struct comedi_insn`, getting the length from the `n_insns` member of the `struct comedi_insnlist` supplied by the user. The allocation will fail with a WARNING and a stack dump if it is too large. Avoid that by failing with an `-EINVAL` error if the supplied `n_insns` value is unreasonable. Define the limit on the `n_insns` value in the `MAX_INSNS` macro. Set this to the same value as `MAX_SAMPLES` (65536), which is the maximum allowed sum of the values of the member `n` in the array of `struct comedi_insn`, and sensible comedi instructions will have an `n` of at least 1. Reported-by: syzbot+d6995b62e5ac7d79557a(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d6995b62e5ac7d79557a Fixes: ed9eccbe8970 ("Staging: add comedi core") Tested-by: Ian Abbott <abbotti(a)mev.co.uk> Cc: <stable(a)vger.kernel.org> # 5.13+ Signed-off-by: Ian Abbott <abbotti(a)mev.co.uk> --- Patch does not apply cleanly to longterm kernels 5.4.x and 5.10.x. --- drivers/comedi/comedi_fops.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c index 3383a7ce27ff..962fb9b18a52 100644 --- a/drivers/comedi/comedi_fops.c +++ b/drivers/comedi/comedi_fops.c @@ -1589,6 +1589,16 @@ static int do_insnlist_ioctl(struct comedi_device *dev, return i; } +#define MAX_INSNS MAX_SAMPLES +static int check_insnlist_len(struct comedi_device *dev, unsigned int n_insns) +{ + if (n_insns > MAX_INSNS) { + dev_dbg(dev->class_dev, "insnlist length too large\n"); + return -EINVAL; + } + return 0; +} + /* * COMEDI_INSN ioctl * synchronous instruction @@ -2239,6 +2249,9 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd, rc = -EFAULT; break; } + rc = check_insnlist_len(dev, insnlist.n_insns); + if (rc) + break; insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL); if (!insns) { rc = -ENOMEM; @@ -3142,6 +3155,9 @@ static int compat_insnlist(struct file *file, unsigned long arg) if (copy_from_user(&insnlist32, compat_ptr(arg), sizeof(insnlist32))) return -EFAULT; + rc = check_insnlist_len(dev, insnlist32.n_insns); + if (rc) + return rc; insns = kcalloc(insnlist32.n_insns, sizeof(*insns), GFP_KERNEL); if (!insns) return -ENOMEM; -- 2.47.2

3 weeks

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[PATCH 5.10] bpf: Reject variable offset alu on PTR_TO_FLOW_KEYS

by Anastasia Belova

From: Hao Sun <sunhao.th(a)gmail.com> [ Upstream commit 22c7fa171a02d310e3a3f6ed46a698ca8a0060ed ] For PTR_TO_FLOW_KEYS, check_flow_keys_access() only uses fixed off for validation. However, variable offset ptr alu is not prohibited for this ptr kind. So the variable offset is not checked. The following prog is accepted: func#0 @0 0: R1=ctx() R10=fp0 0: (bf) r6 = r1 ; R1=ctx() R6_w=ctx() 1: (79) r7 = *(u64 *)(r6 +144) ; R6_w=ctx() R7_w=flow_keys() 2: (b7) r8 = 1024 ; R8_w=1024 3: (37) r8 /= 1 ; R8_w=scalar() 4: (57) r8 &= 1024 ; R8_w=scalar(smin=smin32=0, smax=umax=smax32=umax32=1024,var_off=(0x0; 0x400)) 5: (0f) r7 += r8 mark_precise: frame0: last_idx 5 first_idx 0 subseq_idx -1 mark_precise: frame0: regs=r8 stack= before 4: (57) r8 &= 1024 mark_precise: frame0: regs=r8 stack= before 3: (37) r8 /= 1 mark_precise: frame0: regs=r8 stack= before 2: (b7) r8 = 1024 6: R7_w=flow_keys(smin=smin32=0,smax=umax=smax32=umax32=1024,var_off =(0x0; 0x400)) R8_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=1024, var_off=(0x0; 0x400)) 6: (79) r0 = *(u64 *)(r7 +0) ; R0_w=scalar() 7: (95) exit This prog loads flow_keys to r7, and adds the variable offset r8 to r7, and finally causes out-of-bounds access: BUG: unable to handle page fault for address: ffffc90014c80038 [...] Call Trace: <TASK> bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline] __bpf_prog_run include/linux/filter.h:651 [inline] bpf_prog_run include/linux/filter.h:658 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:675 [inline] bpf_flow_dissect+0x15f/0x350 net/core/flow_dissector.c:991 bpf_prog_test_run_flow_dissector+0x39d/0x620 net/bpf/test_run.c:1359 bpf_prog_test_run kernel/bpf/syscall.c:4107 [inline] __sys_bpf+0xf8f/0x4560 kernel/bpf/syscall.c:5475 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline] __se_sys_bpf kernel/bpf/syscall.c:5559 [inline] __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:5559 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Fix this by rejecting ptr alu with variable offset on flow_keys. Applying the patch rejects the program with "R7 pointer arithmetic on flow_keys prohibited". Fixes: d58e468b1112 ("flow_dissector: implements flow dissector BPF hook") Signed-off-by: Hao Sun <sunhao.th(a)gmail.com> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Acked-by: Yonghong Song <yonghong.song(a)linux.dev> Link: https://lore.kernel.org/bpf/20240115082028.9992-1-sunhao.th@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Anastasia Belova <abelova(a)astralinux.ru> --- Backport fix for CVE-2024-26589 kernel/bpf/verifier.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 75251870430e..2a3b5e4276ba 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6280,6 +6280,10 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n", dst, reg_type_str[ptr_reg->type]); return -EACCES; + case PTR_TO_FLOW_KEYS: + if (known) + break; + fallthrough; case CONST_PTR_TO_MAP: /* smin_val represents the known value */ if (known && smin_val == 0 && opcode == BPF_ADD) -- 2.43.0

3 weeks

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[PATCH 5.15.y] xfs: fix super block buf log item UAF during force shutdown

by Pranav Tyagi

From: Guo Xuenan <guoxuenan(a)huawei.com> [ Upstream commit 575689fc0ffa6c4bb4e72fd18e31a6525a6124e0 ] xfs log io error will trigger xlog shut down, and end_io worker call xlog_state_shutdown_callbacks to unpin and release the buf log item. The race condition is that when there are some thread doing transaction commit and happened not to be intercepted by xlog_is_shutdown, then, these log item will be insert into CIL, when unpin and release these buf log item, UAF will occur. BTW, add delay before `xlog_cil_commit` can increase recurrence probability. The following call graph actually encountered this bad situation. fsstress io end worker kworker/0:1H-216 xlog_ioend_work ->xlog_force_shutdown ->xlog_state_shutdown_callbacks ->xlog_cil_process_committed ->xlog_cil_committed ->xfs_trans_committed_bulk ->xfs_trans_apply_sb_deltas ->li_ops->iop_unpin(lip, 1); ->xfs_trans_getsb ->_xfs_trans_bjoin ->xfs_buf_item_init ->if (bip) { return 0;} //relog ->xlog_cil_commit ->xlog_cil_insert_items //insert into CIL ->xfs_buf_ioend_fail(bp); ->xfs_buf_ioend ->xfs_buf_item_done ->xfs_buf_item_relse ->xfs_buf_item_free when cil push worker gather percpu cil and insert super block buf log item into ctx->log_items then uaf occurs. ================================================================== BUG: KASAN: use-after-free in xlog_cil_push_work+0x1c8f/0x22f0 Write of size 8 at addr ffff88801800f3f0 by task kworker/u4:4/105 CPU: 0 PID: 105 Comm: kworker/u4:4 Tainted: G W 6.1.0-rc1-00001-g274115149b42 #136 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: xfs-cil/sda xlog_cil_push_work Call Trace: <TASK> dump_stack_lvl+0x4d/0x66 print_report+0x171/0x4a6 kasan_report+0xb3/0x130 xlog_cil_push_work+0x1c8f/0x22f0 process_one_work+0x6f9/0xf70 worker_thread+0x578/0xf30 kthread+0x28c/0x330 ret_from_fork+0x1f/0x30 </TASK> Allocated by task 2145: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_slab_alloc+0x54/0x60 kmem_cache_alloc+0x14a/0x510 xfs_buf_item_init+0x160/0x6d0 _xfs_trans_bjoin+0x7f/0x2e0 xfs_trans_getsb+0xb6/0x3f0 xfs_trans_apply_sb_deltas+0x1f/0x8c0 __xfs_trans_commit+0xa25/0xe10 xfs_symlink+0xe23/0x1660 xfs_vn_symlink+0x157/0x280 vfs_symlink+0x491/0x790 do_symlinkat+0x128/0x220 __x64_sys_symlink+0x7a/0x90 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 216: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x40 __kasan_slab_free+0x105/0x1a0 kmem_cache_free+0xb6/0x460 xfs_buf_ioend+0x1e9/0x11f0 xfs_buf_item_unpin+0x3d6/0x840 xfs_trans_committed_bulk+0x4c2/0x7c0 xlog_cil_committed+0xab6/0xfb0 xlog_cil_process_committed+0x117/0x1e0 xlog_state_shutdown_callbacks+0x208/0x440 xlog_force_shutdown+0x1b3/0x3a0 xlog_ioend_work+0xef/0x1d0 process_one_work+0x6f9/0xf70 worker_thread+0x578/0xf30 kthread+0x28c/0x330 ret_from_fork+0x1f/0x30 The buggy address belongs to the object at ffff88801800f388 which belongs to the cache xfs_buf_item of size 272 The buggy address is located 104 bytes inside of 272-byte region [ffff88801800f388, ffff88801800f498) The buggy address belongs to the physical page: page:ffffea0000600380 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801800f208 pfn:0x1800e head:ffffea0000600380 order:1 compound_mapcount:0 compound_pincount:0 flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) raw: 001fffff80010200 ffffea0000699788 ffff88801319db50 ffff88800fb50640 raw: ffff88801800f208 000000000015000a 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88801800f280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801800f300: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88801800f380: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801800f400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801800f480: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Disabling lock debugging due to kernel taint [ Backport to 5.15: context cleanly applied with no semantic changes. Build-tested. ] Signed-off-by: Guo Xuenan <guoxuenan(a)huawei.com> Reviewed-by: Darrick J. Wong <djwong(a)kernel.org> Signed-off-by: Darrick J. Wong <djwong(a)kernel.org> Signed-off-by: Pranav Tyagi <pranav.tyagi03(a)gmail.com> --- fs/xfs/xfs_buf_item.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index b1ab100c09e1..ffe318eb897f 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -1017,6 +1017,8 @@ xfs_buf_item_relse( trace_xfs_buf_item_relse(bp, _RET_IP_); ASSERT(!test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags)); + if (atomic_read(&bip->bli_refcount)) + return; bp->b_log_item = NULL; xfs_buf_rele(bp); xfs_buf_item_free(bip); -- 2.49.0

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[PATCH v2] drm/gem: Acquire references on GEM handles for framebuffers

by Thomas Zimmermann

A GEM handle can be released while the GEM buffer object is attached to a DRM framebuffer. This leads to the release of the dma-buf backing the buffer object, if any. [1] Trying to use the framebuffer in further mode-setting operations leads to a segmentation fault. Most easily happens with driver that use shadow planes for vmap-ing the dma-buf during a page flip. An example is shown below. [ 156.791968] ------------[ cut here ]------------ [ 156.796830] WARNING: CPU: 2 PID: 2255 at drivers/dma-buf/dma-buf.c:1527 dma_buf_vmap+0x224/0x430 [...] [ 156.942028] RIP: 0010:dma_buf_vmap+0x224/0x430 [ 157.043420] Call Trace: [ 157.045898] <TASK> [ 157.048030] ? show_trace_log_lvl+0x1af/0x2c0 [ 157.052436] ? show_trace_log_lvl+0x1af/0x2c0 [ 157.056836] ? show_trace_log_lvl+0x1af/0x2c0 [ 157.061253] ? drm_gem_shmem_vmap+0x74/0x710 [ 157.065567] ? dma_buf_vmap+0x224/0x430 [ 157.069446] ? __warn.cold+0x58/0xe4 [ 157.073061] ? dma_buf_vmap+0x224/0x430 [ 157.077111] ? report_bug+0x1dd/0x390 [ 157.080842] ? handle_bug+0x5e/0xa0 [ 157.084389] ? exc_invalid_op+0x14/0x50 [ 157.088291] ? asm_exc_invalid_op+0x16/0x20 [ 157.092548] ? dma_buf_vmap+0x224/0x430 [ 157.096663] ? dma_resv_get_singleton+0x6d/0x230 [ 157.101341] ? __pfx_dma_buf_vmap+0x10/0x10 [ 157.105588] ? __pfx_dma_resv_get_singleton+0x10/0x10 [ 157.110697] drm_gem_shmem_vmap+0x74/0x710 [ 157.114866] drm_gem_vmap+0xa9/0x1b0 [ 157.118763] drm_gem_vmap_unlocked+0x46/0xa0 [ 157.123086] drm_gem_fb_vmap+0xab/0x300 [ 157.126979] drm_atomic_helper_prepare_planes.part.0+0x487/0xb10 [ 157.133032] ? lockdep_init_map_type+0x19d/0x880 [ 157.137701] drm_atomic_helper_commit+0x13d/0x2e0 [ 157.142671] ? drm_atomic_nonblocking_commit+0xa0/0x180 [ 157.147988] drm_mode_atomic_ioctl+0x766/0xe40 [...] [ 157.346424] ---[ end trace 0000000000000000 ]--- Acquiring GEM handles for the framebuffer's GEM buffer objects prevents this from happening. The framebuffer's cleanup later puts the handle references. Commit 1a148af06000 ("drm/gem-shmem: Use dma_buf from GEM object instance") triggers the segmentation fault easily by using the dma-buf field more widely. The underlying issue with reference counting has been present before. v2: - acquire the handle instead of the BO (Christian) - fix comment style (Christian) - drop the Fixes tag (Christian) - rename err_ gotos - add missing Link tag Suggested-by: Christian König <christian.koenig(a)amd.com> Signed-off-by: Thomas Zimmermann <tzimmermann(a)suse.de> Link: https://elixir.bootlin.com/linux/v6.15/source/drivers/gpu/drm/drm_gem.c#L241 # [1] Cc: Thomas Zimmermann <tzimmermann(a)suse.de> Cc: Anusha Srivatsa <asrivats(a)redhat.com> Cc: Christian König <christian.koenig(a)amd.com> Cc: Maarten Lankhorst <maarten.lankhorst(a)linux.intel.com> Cc: Maxime Ripard <mripard(a)kernel.org> Cc: Sumit Semwal <sumit.semwal(a)linaro.org> Cc: "Christian König" <christian.koenig(a)amd.com> Cc: linux-media(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: linaro-mm-sig(a)lists.linaro.org Cc: <stable(a)vger.kernel.org> --- drivers/gpu/drm/drm_gem.c | 44 ++++++++++++++++++-- drivers/gpu/drm/drm_gem_framebuffer_helper.c | 16 +++---- drivers/gpu/drm/drm_internal.h | 2 + 3 files changed, 51 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 19d50d254fe6..bc505d938b3e 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -213,6 +213,35 @@ void drm_gem_private_object_fini(struct drm_gem_object *obj) } EXPORT_SYMBOL(drm_gem_private_object_fini); +static void drm_gem_object_handle_get(struct drm_gem_object *obj) +{ + struct drm_device *dev = obj->dev; + + drm_WARN_ON(dev, !mutex_is_locked(&dev->object_name_lock)); + + if (obj->handle_count++ == 0) + drm_gem_object_get(obj); +} + +/** + * drm_gem_object_handle_get_unlocked - acquire reference on user-space handles + * @obj: GEM object + * + * Acquires a reference on the GEM buffer object's handle. Required + * to keep the GEM object alive. Call drm_gem_object_handle_put_unlocked() + * to release the reference. + */ +void drm_gem_object_handle_get_unlocked(struct drm_gem_object *obj) +{ + struct drm_device *dev = obj->dev; + + guard(mutex)(&dev->object_name_lock); + + drm_WARN_ON(dev, !obj->handle_count); /* first ref taken in create-tail helper */ + drm_gem_object_handle_get(obj); +} +EXPORT_SYMBOL(drm_gem_object_handle_get_unlocked); + /** * drm_gem_object_handle_free - release resources bound to userspace handles * @obj: GEM object to clean up. @@ -243,8 +272,14 @@ static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj) } } -static void -drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj) +/** + * drm_gem_object_handle_put_unlocked - releases reference on user-space handles + * @obj: GEM object + * + * Releases a reference on the GEM buffer object's handle. Possibly releases + * the GEM buffer object and associated dma-buf objects. + */ +void drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj) { struct drm_device *dev = obj->dev; bool final = false; @@ -269,6 +304,7 @@ drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj) if (final) drm_gem_object_put(obj); } +EXPORT_SYMBOL(drm_gem_object_handle_put_unlocked); /* * Called at device or object close to release the file's @@ -390,8 +426,8 @@ drm_gem_handle_create_tail(struct drm_file *file_priv, int ret; WARN_ON(!mutex_is_locked(&dev->object_name_lock)); - if (obj->handle_count++ == 0) - drm_gem_object_get(obj); + + drm_gem_object_handle_get(obj); /* * Get the user-visible handle using idr. Preload and perform diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c index 618ce725cd75..c60d0044d036 100644 --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c @@ -100,7 +100,7 @@ void drm_gem_fb_destroy(struct drm_framebuffer *fb) unsigned int i; for (i = 0; i < fb->format->num_planes; i++) - drm_gem_object_put(fb->obj[i]); + drm_gem_object_handle_put_unlocked(fb->obj[i]); drm_framebuffer_cleanup(fb); kfree(fb); @@ -183,8 +183,10 @@ int drm_gem_fb_init_with_funcs(struct drm_device *dev, if (!objs[i]) { drm_dbg_kms(dev, "Failed to lookup GEM object\n"); ret = -ENOENT; - goto err_gem_object_put; + goto err_gem_object_handle_put_unlocked; } + drm_gem_object_handle_get_unlocked(objs[i]); + drm_gem_object_put(objs[i]); min_size = (height - 1) * mode_cmd->pitches[i] + drm_format_info_min_pitch(info, i, width) @@ -194,22 +196,22 @@ int drm_gem_fb_init_with_funcs(struct drm_device *dev, drm_dbg_kms(dev, "GEM object size (%zu) smaller than minimum size (%u) for plane %d\n", objs[i]->size, min_size, i); - drm_gem_object_put(objs[i]); + drm_gem_object_handle_put_unlocked(objs[i]); ret = -EINVAL; - goto err_gem_object_put; + goto err_gem_object_handle_put_unlocked; } } ret = drm_gem_fb_init(dev, fb, mode_cmd, objs, i, funcs); if (ret) - goto err_gem_object_put; + goto err_gem_object_handle_put_unlocked; return 0; -err_gem_object_put: +err_gem_object_handle_put_unlocked: while (i > 0) { --i; - drm_gem_object_put(objs[i]); + drm_gem_object_handle_put_unlocked(objs[i]); } return ret; } diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h index 442eb31351dd..f7b414a813ae 100644 --- a/drivers/gpu/drm/drm_internal.h +++ b/drivers/gpu/drm/drm_internal.h @@ -161,6 +161,8 @@ void drm_sysfs_lease_event(struct drm_device *dev); /* drm_gem.c */ int drm_gem_init(struct drm_device *dev); +void drm_gem_object_handle_get_unlocked(struct drm_gem_object *obj); +void drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj); int drm_gem_handle_create_tail(struct drm_file *file_priv, struct drm_gem_object *obj, u32 *handlep); -- 2.50.0

3 weeks

3
14
0 0

[REGRESSION] Packet loss after hot-plugging ethernet cable on HP Zbook (Arrow Lake)

by En-Wei WU

Hi, I'm seeing a regression on an HP ZBook using the e1000e driver (chipset PCI ID: [8086:57a0]) -- the system can't get an IP address after hot-plugging an Ethernet cable. In this case, the Ethernet cable was unplugged at boot. The network interface eno1 was present but stuck in the DHCP process. Using tcpdump, only TX packets were visible and never got any RX -- indicating a possible packet loss or link-layer issue. This is on the vanilla Linux 6.16-rc4 (commit 62f224733431dbd564c4fe800d4b67a0cf92ed10). Bisect says it's this commit: commit efaaf344bc2917cbfa5997633bc18a05d3aed27f Author: Vitaly Lifshits <vitaly.lifshits(a)intel.com> Date: Thu Mar 13 16:05:56 2025 +0200 e1000e: change k1 configuration on MTP and later platforms Starting from Meteor Lake, the Kumeran interface between the integrated MAC and the I219 PHY works at a different frequency. This causes sporadic MDI errors when accessing the PHY, and in rare circumstances could lead to packet corruption. To overcome this, introduce minor changes to the Kumeran idle state (K1) parameters during device initialization. Hardware reset reverts this configuration, therefore it needs to be applied in a few places. Fixes: cc23f4f0b6b9 ("e1000e: Add support for Meteor Lake") Signed-off-by: Vitaly Lifshits <vitaly.lifshits(a)intel.com> Tested-by: Avigail Dahan <avigailx.dahan(a)intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen(a)intel.com> drivers/net/ethernet/intel/e1000e/defines.h | 3 +++ drivers/net/ethernet/intel/e1000e/ich8lan.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----- drivers/net/ethernet/intel/e1000e/ich8lan.h | 4 ++++ 3 files changed, 82 insertions(+), 5 deletions(-) Reverting this patch resolves the issue. Based on the symptoms and the bisect result, this issue might be similar to https://lore.kernel.org/intel-wired-lan/20250626153544.1853d106@onyx.my.dom… Affected machine is: HP ZBook X G1i 16 inch Mobile Workstation PC, BIOS 01.02.03 05/27/2025 (see end of message for dmesg from boot) CPU model name: Intel(R) Core(TM) Ultra 7 265H (Arrow Lake) ethtool output: driver: e1000e version: 6.16.0-061600rc4-generic firmware-version: 0.1-4 expansion-rom-version: bus-info: 0000:00:1f.6 supports-statistics: yes supports-test: yes supports-eeprom-access: yes supports-register-dump: yes supports-priv-flags: yes lspci output: 0:1f.6 Ethernet controller [0200]: Intel Corporation Device [8086:57a0] DeviceName: Onboard Ethernet Subsystem: Hewlett-Packard Company Device [103c:8e1d] Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin D routed to IRQ 162 IOMMU group: 17 Region 0: Memory at 92280000 (32-bit, non-prefetchable) [size=128K] Capabilities: [c8] Power Management version 3 Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+) Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=1 PME- Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+ Address: 00000000fee00798 Data: 0000 Kernel driver in use: e1000e Kernel modules: e1000e The relevant dmesg: <<<cable disconnected>>> [ 0.927394] e1000e: Intel(R) PRO/1000 Network Driver [ 0.927398] e1000e: Copyright(c) 1999 - 2015 Intel Corporation. [ 0.927933] e1000e 0000:00:1f.6: enabling device (0000 -> 0002) [ 0.928249] e1000e 0000:00:1f.6: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode [ 1.155716] e1000e 0000:00:1f.6 0000:00:1f.6 (uninitialized): registered PHC clock [ 1.220694] e1000e 0000:00:1f.6 eth0: (PCI Express:2.5GT/s:Width x1) 24:fb:e3:bf:28:c6 [ 1.220721] e1000e 0000:00:1f.6 eth0: Intel(R) PRO/1000 Network Connection [ 1.220903] e1000e 0000:00:1f.6 eth0: MAC: 16, PHY: 12, PBA No: FFFFFF-0FF [ 1.222632] e1000e 0000:00:1f.6 eno1: renamed from eth0 <<<cable connected>>> [ 153.932626] e1000e 0000:00:1f.6 eno1: NIC Link is Up 1000 Mbps Half Duplex, Flow Control: None [ 153.934527] e1000e 0000:00:1f.6 eno1: NIC Link is Down [ 157.622238] e1000e 0000:00:1f.6 eno1: NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None No error message seen after hot-plugging the Ethernet cable. -- Best Regards, En-Wei.

3 weeks

3
3
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[PATCH] ALSA: ad1816a: Fix potential NULL pointer deref in snd_card_ad1816a_pnp()

by Thorsten Blum

Use pr_warn() instead of dev_warn() when 'pdev' is NULL to avoid a potential NULL pointer dereference. Cc: stable(a)vger.kernel.org Fixes: 20869176d7a7 ("ALSA: ad1816a: Use standard print API") Signed-off-by: Thorsten Blum <thorsten.blum(a)linux.dev> --- sound/isa/ad1816a/ad1816a.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/isa/ad1816a/ad1816a.c b/sound/isa/ad1816a/ad1816a.c index 99006dc4777e..5c9e2d41d900 100644 --- a/sound/isa/ad1816a/ad1816a.c +++ b/sound/isa/ad1816a/ad1816a.c @@ -98,7 +98,7 @@ static int snd_card_ad1816a_pnp(int dev, struct pnp_card_link *card, pdev = pnp_request_card_device(card, id->devs[1].id, NULL); if (pdev == NULL) { mpu_port[dev] = -1; - dev_warn(&pdev->dev, "MPU401 device busy, skipping.\n"); + pr_warn("MPU401 device busy, skipping.\n"); return 0; } -- 2.50.0

3 weeks

2
1
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[PATCH 1/2] KVM: arm64: Fix enforcement of upper bound on MDCR_EL2.HPMN

by Ben Horgan

Previously, u64_replace_bits() was used to no effect as the return value was ignored. Convert to u64p_replace_bits() so the value is updated in place. Signed-off-by: Ben Horgan <ben.horgan(a)arm.com> Fixes: efff9dd2fee7 ("KVM: arm64: Handle out-of-bound write to MDCR_EL2.HPMN") Cc: Marc Zyngier <maz(a)kernel.org> Cc: stable(a)vger.kernel.org --- arch/arm64/kvm/sys_regs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 76c2f0da821f..c20bd6f21e60 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2624,7 +2624,7 @@ static bool access_mdcr(struct kvm_vcpu *vcpu, */ if (hpmn > vcpu->kvm->arch.nr_pmu_counters) { hpmn = vcpu->kvm->arch.nr_pmu_counters; - u64_replace_bits(val, hpmn, MDCR_EL2_HPMN); + u64p_replace_bits(&val, hpmn, MDCR_EL2_HPMN); } __vcpu_assign_sys_reg(vcpu, MDCR_EL2, val); -- 2.43.0

3 weeks

2
1
0 0

+ mm-damon-fix-divide-by-zero-in-damon_get_intervals_score.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm/damon: fix divide by zero in damon_get_intervals_score() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-damon-fix-divide-by-zero-in-damon_get_intervals_score.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Honggyu Kim <honggyu.kim(a)sk.com> Subject: mm/damon: fix divide by zero in damon_get_intervals_score() Date: Wed, 2 Jul 2025 09:02:04 +0900 The current implementation allows having zero size regions with no special reasons, but damon_get_intervals_score() gets crashed by divide by zero when the region size is zero. [ 29.403950] Oops: divide error: 0000 [#1] SMP NOPTI This patch fixes the bug, but does not disallow zero size regions to keep the backward compatibility since disallowing zero size regions might be a breaking change for some users. In addition, the same crash can happen when intervals_goal.access_bp is zero so this should be fixed in stable trees as well. Link: https://lkml.kernel.org/r/20250702000205.1921-5-honggyu.kim@sk.com Fixes: f04b0fedbe71 ("mm/damon/core: implement intervals auto-tuning") Signed-off-by: Honggyu Kim <honggyu.kim(a)sk.com> Reviewed-by: SeongJae Park <sj(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/damon/core.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/damon/core.c~mm-damon-fix-divide-by-zero-in-damon_get_intervals_score +++ a/mm/damon/core.c @@ -1449,6 +1449,7 @@ static unsigned long damon_get_intervals } } target_access_events = max_access_events * goal_bp / 10000; + target_access_events = target_access_events ? : 1; return access_events * 10000 / target_access_events; } _ Patches currently in -mm which might be from honggyu.kim(a)sk.com are samples-damon-fix-damon-sample-prcl-for-start-failure.patch samples-damon-fix-damon-sample-wsse-for-start-failure.patch samples-damon-fix-damon-sample-mtier-for-start-failure.patch mm-damon-fix-divide-by-zero-in-damon_get_intervals_score.patch

3 weeks

1
0
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+ samples-damon-fix-damon-sample-mtier-for-start-failure.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: samples/damon: fix damon sample mtier for start failure has been added to the -mm mm-hotfixes-unstable branch. Its filename is samples-damon-fix-damon-sample-mtier-for-start-failure.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Honggyu Kim <honggyu.kim(a)sk.com> Subject: samples/damon: fix damon sample mtier for start failure Date: Wed, 2 Jul 2025 09:02:03 +0900 The damon_sample_mtier_start() can fail so we must reset the "enable" parameter to "false" again for proper rollback. In such cases, setting Y to "enable" then N triggers the similar crash with mtier because damon sample start failed but the "enable" stays as Y. Link: https://lkml.kernel.org/r/20250702000205.1921-4-honggyu.kim@sk.com Fixes: 82a08bde3cf7 ("samples/damon: implement a DAMON module for memory tiering") Signed-off-by: Honggyu Kim <honggyu.kim(a)sk.com> Reviewed-by: SeongJae Park <sj(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- samples/damon/mtier.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/samples/damon/mtier.c~samples-damon-fix-damon-sample-mtier-for-start-failure +++ a/samples/damon/mtier.c @@ -164,8 +164,12 @@ static int damon_sample_mtier_enable_sto if (enable == enabled) return 0; - if (enable) - return damon_sample_mtier_start(); + if (enable) { + err = damon_sample_mtier_start(); + if (err) + enable = false; + return err; + } damon_sample_mtier_stop(); return 0; } _ Patches currently in -mm which might be from honggyu.kim(a)sk.com are samples-damon-fix-damon-sample-prcl-for-start-failure.patch samples-damon-fix-damon-sample-wsse-for-start-failure.patch samples-damon-fix-damon-sample-mtier-for-start-failure.patch mm-damon-fix-divide-by-zero-in-damon_get_intervals_score.patch

3 weeks

1
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