Re: [PATCH 1/2] firewire: Kill unnecessary buf check in device_attribute.show
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From: Takashi S. <o-t...@sa...> - 2024-03-18 04:46:30
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Hi, On Mon, Jan 22, 2024 at 05:56:04PM +0900, Takashi Sakamoto wrote: > Hi, > > On Mon, Jan 22, 2024 at 01:39:41PM +0800, Li Zhijian wrote: > > Per Documentation/filesystems/sysfs.rst: > > > sysfs allocates a buffer of size (PAGE_SIZE) and passes it to the > > > method. > > > > So we can kill the unnecessary buf check safely. > > > > Signed-off-by: Li Zhijian <liz...@fu...> > > --- > > drivers/firewire/core-device.c | 14 +++----------- > > 1 file changed, 3 insertions(+), 11 deletions(-) > > Applied both patches to linux-next branch, since they are not so-urgent > fixes. I realized that it causes an issue at the path to initialize device structure for node in IEEE 1394 bus. (drivers/firewire/core-device.c) fw_device_init() / fw_device_refresh() ->create_units() ->init_fw_attribute_group() ->attr->show(dev, attr, NULL) kernel: ------------[ cut here ]------------ kernel: invalid sysfs_emit: buf:0000000000000000 kernel: WARNING: CPU: 5 PID: 647501 at fs/sysfs/file.c:747 sysfs_emit+0xb5/0xc0 kernel: Modules linked in: snd_fireworks(OE) snd_firewire_lib(OE) firewire_ohci(OE) firewire_core(OE) cfg80211 veth nft_masq crc_itu_t vfio_pci vfio_pci_core vfio_iommu_type1 vfio iommufd rpcsec_gss_krb5 nfsv4 nfs netfs snd_seq_dummy sn> kernel: crypto_simd asus_wmi snd_timer ledtrig_audio cryptd cec sparse_keymap nls_iso8859_1 rapl platform_profile wmi_bmof k10temp i2c_piix4 snd rc_core i2c_algo_bit ccp soundcore zfs(PO) spl(O) input_leds joydev cdc_mbim cdc_wdm mac_h> kernel: CPU: 5 PID: 647501 Comm: kworker/5:0 Tainted: P W OE 6.8.0-11-generic #11-Ubuntu kernel: Hardware name: System manufacturer System Product Name/TUF GAMING X570-PLUS, BIOS 5003 10/07/2023 kernel: Workqueue: firewire fw_device_workfn [firewire_core] kernel: RIP: 0010:sysfs_emit+0xb5/0xc0 kernel: Code: 25 28 00 00 00 75 29 c9 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 e9 5a 89 c7 00 48 89 fe 48 c7 c7 64 06 3f bd e8 1b 80 b4 ff <0f> 0b 31 c0 eb c7 e8 a0 ea c5 00 90 90 90 90 90 90 90 90 90 90 90 kernel: RSP: 0018:ffffacd857103cd0 EFLAGS: 00010246 kernel: RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 kernel: RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 kernel: RBP: ffffacd857103d20 R08: 0000000000000000 R09: 0000000000000000 kernel: R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000010000 kernel: R13: ffffffffc28e2ff8 R14: 0000000000000000 R15: 0000000000000001 kernel: FS: 0000000000000000(0000) GS:ffff918190080000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kernel: CR2: 00007835dca0b048 CR3: 00000003cb898000 CR4: 00000000003506f0 kernel: Call Trace: kernel: <TASK> kernel: ? show_regs+0x6d/0x80 kernel: ? __warn+0x89/0x160 kernel: ? sysfs_emit+0xb5/0xc0 kernel: ? report_bug+0x17e/0x1b0 kernel: ? handle_bug+0x51/0xa0 kernel: ? exc_invalid_op+0x18/0x80 kernel: ? asm_exc_invalid_op+0x1b/0x20 kernel: ? sysfs_emit+0xb5/0xc0 kernel: show_immediate+0x13f/0x1d0 [firewire_core] kernel: init_fw_attribute_group+0x81/0x150 [firewire_core] kernel: create_units+0x119/0x160 [firewire_core] kernel: fw_device_init+0x1a9/0x330 [firewire_core] kernel: fw_device_workfn+0x12/0x20 [firewire_core] kernel: process_one_work+0x16f/0x350 kernel: worker_thread+0x306/0x440 kernel: ? __pfx_worker_thread+0x10/0x10 kernel: kthread+0xf2/0x120 kernel: ? __pfx_kthread+0x10/0x10 kernel: ret_from_fork+0x47/0x70 kernel: ? __pfx_kthread+0x10/0x10 kernel: ret_from_fork_asm+0x1b/0x30 kernel: </TASK> kernel: ---[ end trace 0000000000000000 ]--- kernel: ------------[ cut here ]------------ Furthermore, 'show_text_leaf()' returns negative value when the NULL pointer is passed. It results in the lack of vendor/model names from sysfs. I absolutely overlooked them. I would like to fix them within this merge window, or revert them as a last resort... Regards Takashi Sakamoto |