On 12.10.2021 20:59, Qian Cai wrote:
>
>
> On 9/10/2021 2:22 AM, Heiner Kallweit wrote:
>> In certain cases we need a variant of pci_read_vpd()/pci_write_vpd() that
>> does not check against dev->vpd.len. Such cases are:
>> - reading VPD if dev->vpd.len isn't set yet (in pci_vpd_size())
>> - devices that map non-VPD information to arbitrary places in VPD address
>> space (example: Chelsio T3 EEPROM write-protect flag)
>> Therefore add function variants that check against PCI_VPD_MAX_SIZE only.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx
> Reverting this series fixed a hang or stack overflow while reading things like,
>
> /sys/devices/pci0000:00/0000:00:00.0/0000:01:00.0/vpd
>
> [ 125.797082] Insufficient stack space to handle exception!
> [ 125.797091] ESR: 0x96000047 -- DABT (current EL)
> [ 125.797095] FAR: 0xffff80002433ffc0
> [ 125.797096] Task stack: [0xffff800024340000..0xffff800024350000]
> [ 125.797099] IRQ stack: [0xffff8000101c0000..0xffff8000101d0000]
> [ 125.797102] Overflow stack: [0xffff009b675b02b0..0xffff009b675b12b0]
> [ 125.797106] CPU: 14 PID: 1550 Comm: lsbug Not tainted 5.15.0-rc5-next-20211012 #143
> [ 125.797110] Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.6 06/28/2020
> [ 125.797114] pstate: 10000005 (nzcV daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [ 125.797118] pc : pci_vpd_size+0xc/0x1f8
> [ 125.797128] lr : pci_vpd_read+0x2ec/0x420
> [ 125.797132] sp : ffff800024340060
> [ 125.797133] x29: ffff800024340060 x28: ffff00001a54cbcc x27: 0000000000000000
> [ 125.797142] x26: ffff800024340210 x25: 0000000000000004 x24: 1fffe000034a9979
> [ 125.797148] x23: ffff00001a54cbc8 x22: ffff00001a54cb38 x21: 0000000000008000
> [ 125.797153] x20: 1fffe000034a9979 x19: ffff00001a54c000 x18: 0000000000000000
> [ 125.797158] x17: 0000000000000000 x16: 0000000000000000 x15: dfff800000000000
> [ 125.797163] x14: ffff800019ab0560 x13: 1fffe00110f9272f x12: ffff60010e945be1
> [ 125.797168] x11: 1fffe0010e945be0 x10: 1ffff00004868022 x9 : ffff800010d1a38c
> [ 125.797174] x8 : ffff700004868022 x7 : dfff800000000000 x6 : 0000000000000000
> [ 125.797179] x5 : ffff000887c93540 x4 : 0000000000000000 x3 : ffff800024340210
> [ 125.797184] x2 : 0000000000000001 x1 : 0000000000000003 x0 : ffff00001a54c000
> [ 125.797190] Kernel panic - not syncing: kernel stack overflow
> [ 125.797193] CPU: 14 PID: 1550 Comm: lsbug Not tainted 5.15.0-rc5-next-20211012 #143
> [ 125.797197] Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.6 06/28/2020
> [ 125.797199] Call trace:
> [ 125.797201] dump_backtrace+0x0/0x3b8
> [ 125.797208] show_stack+0x20/0x30
> [ 125.797212] dump_stack_lvl+0x8c/0xb8
> [ 125.797216] dump_stack+0x1c/0x38
> [ 125.797219] panic+0x2b0/0x538
> [ 125.797224] add_taint+0x0/0xe8
> [ 125.797229] panic_bad_stack+0x1e4/0x230
> [ 125.797233] handle_bad_stack+0x38/0x50
> [ 125.797237] __bad_stack+0x88/0x8c
> [ 125.797241] pci_vpd_size+0xc/0x1f8
> [ 125.797244] __pci_read_vpd+0x114/0x158
> [ 125.797247] pci_vpd_size+0xa0/0x1f8
> [ 125.797251] pci_vpd_read+0x2ec/0x420
> [ 125.797254] __pci_read_vpd+0x114/0x158
> [ 125.797258] pci_vpd_size+0xa0/0x1f8
> [ 125.797261] pci_vpd_read+0x2ec/0x420
> ...
> [ 125.798534] __pci_read_vpd+0x114/0x158
> [ 125.798538] pci_vpd_size+0xa0/0x1f8
> [ 125.798541] pci_vpd_read+0x2ec/0x420
> [ 125.798545] __pci_read_vpd+0x114/0x158
> __pci_read_vpd at /usr/src/linux-next/drivers/pci/vpd.c:398
> [ 125.798548] vpd_read+0x28/0x38
> vpd_read at /usr/src/linux-next/drivers/pci/vpd.c:276
> [ 125.798551] sysfs_kf_bin_read+0x120/0x218
> [ 125.798556] kernfs_fop_read_iter+0x244/0x4a8
> [ 125.798559] new_sync_read+0x2bc/0x4e8
> [ 125.798564] vfs_read+0x18c/0x390
> [ 125.798567] ksys_read+0xf8/0x1e0
> [ 125.798570] __arm64_sys_read+0x74/0xa8
> [ 125.798574] invoke_syscall.constprop.0+0xdc/0x1d8
> [ 125.798578] do_el0_svc+0xe4/0x298
> [ 125.798582] el0_svc+0x64/0x130
> [ 125.798586] el0t_64_sync_handler+0xb0/0xb8
> [ 125.798590] el0t_64_sync+0x180/0x184
> [ 125.798598] ------------[ cut here ]------------
> [ 125.798600] WARNING: CPU: -32 PID: 1550 at include/linux/cpumask.h:108 smp_send_stop+0x4a4/0x5e8
> [ 125.798607] Modules linked in: loop cppc_cpufreq efivarfs ip_tables x_tables ext4 mbcache jbd2 dm_mod igb i2c_algo_bit nvme mlx5_core i2c_core nvme_core firmware_class
> [ 125.798632] CPU: 791961908 PID: 1550 Comm: lsbug Not tainted 5.15.0-rc5-next-20211012 #143
> [ 125.798637] Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.6 06/28/2020
> [ 125.798639] pstate: a00003c5 (NzCv DAIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [ 125.798643] pc : smp_send_stop+0x4a4/0x5e8
> [ 125.798647] lr : panic+0x2b8/0x538
> [ 125.798650] sp : ffff009b675b0c70
> [ 125.798652] x29: ffff009b675b0c70 x28: ffff000887c92ec0 x27: 0000000000000000
> [ 125.798658] x26: 0000000000000025 x25: ffff809b55bf0000 x24: ffff800011eeb4d0
> [ 125.798663] x23: ffff800011426680 x22: ffff800019393000 x21: ffff800019dfa000
> [ 125.798668] x20: 00000000ffffffe0 x19: ffff8000119c0000 x18: 0000000000000000
> [ 125.798673] x17: 0000000000000000 x16: 0000000000000002 x15: 0000000000000000
> [ 125.798678] x14: 0000000000000000 x13: 000000000000000f x12: ffff7000023ef669
> [ 125.798683] x11: 1ffff000023ef668 x10: ffff7000023ef668 x9 : ffff80001133f2cc
> [ 125.798688] x8 : 0000000000000003 x7 : 0000000000000001 x6 : ffff800011f7b340
> [ 125.798693] x5 : 1fffe0136ceb619e x4 : 0000000041b58ab3 x3 : 1fffe0136ceb6000
> [ 125.798698] x2 : 1ffff000023dd69a x1 : 0000000000000000 x0 : 0000000000000020
> [ 125.798704] Call trace:
> [ 125.798705] smp_send_stop+0x4a4/0x5e8
> [ 125.798709] panic+0x2b8/0x538
> [ 125.798713] add_taint+0x0/0xe8
> [ 125.798717] panic_bad_stack+0x1e4/0x230
> [ 125.798720] handle_bad_stack+0x38/0x50
> [ 125.798724] __bad_stack+0x88/0x8c
> [ 125.798727] pci_vpd_size+0xc/0x1f8
> [ 125.798731] __pci_read_vpd+0x114/0x158
> [ 125.798734] pci_vpd_size+0xa0/0x1f8
> [ 125.798738] pci_vpd_read+0x2ec/0x420
> [ 125.798741] __pci_read_vpd+0x114/0x158
> [ 125.798744] pci_vpd_size+0xa0/0x1f8
> [ 125.798748] pci_vpd_read+0x2ec/0x420
>
Thanks for the report! I could reproduce the issue, the following fixes
it for me. Could you please test whether it fixes the issue for you as well?
Thank you.
diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
index 5108bbd20..a4fc4d069 100644
--- a/drivers/pci/vpd.c
+++ b/drivers/pci/vpd.c
@@ -96,14 +96,14 @@ static size_t pci_vpd_size(struct pci_dev *dev)
return off ?: PCI_VPD_SZ_INVALID;
}
-static bool pci_vpd_available(struct pci_dev *dev)
+static bool pci_vpd_available(struct pci_dev *dev, bool check_size)
{
struct pci_vpd *vpd = &dev->vpd;
if (!vpd->cap)
return false;
- if (vpd->len == 0) {
+ if (vpd->len == 0 && check_size) {
vpd->len = pci_vpd_size(dev);
if (vpd->len == PCI_VPD_SZ_INVALID) {
vpd->cap = 0;
@@ -156,17 +156,19 @@ static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count,
void *arg, bool check_size)
{
struct pci_vpd *vpd = &dev->vpd;
- unsigned int max_len = check_size ? vpd->len : PCI_VPD_MAX_SIZE;
+ unsigned int max_len;
int ret = 0;
loff_t end = pos + count;
u8 *buf = arg;
- if (!pci_vpd_available(dev))
+ if (!pci_vpd_available(dev, check_size))
return -ENODEV;
if (pos < 0)
return -EINVAL;
+ max_len = check_size ? vpd->len : PCI_VPD_MAX_SIZE;
+
if (pos >= max_len)
return 0;
@@ -218,17 +220,19 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
const void *arg, bool check_size)
{
struct pci_vpd *vpd = &dev->vpd;
- unsigned int max_len = check_size ? vpd->len : PCI_VPD_MAX_SIZE;
+ unsigned int max_len;
const u8 *buf = arg;
loff_t end = pos + count;
int ret = 0;
- if (!pci_vpd_available(dev))
+ if (!pci_vpd_available(dev, check_size))
return -ENODEV;
if (pos < 0 || (pos & 3) || (count & 3))
return -EINVAL;
+ max_len = check_size ? vpd->len : PCI_VPD_MAX_SIZE;
+
if (end > max_len)
return -EINVAL;
@@ -312,7 +316,7 @@ void *pci_vpd_alloc(struct pci_dev *dev, unsigned int *size)
void *buf;
int cnt;
- if (!pci_vpd_available(dev))
+ if (!pci_vpd_available(dev, true))
return ERR_PTR(-ENODEV);
len = dev->vpd.len;
--
2.33.0
