[RESEND PATCH 0/1] mcb: error for not supported devices.

[RESEND PATCH 0/1] mcb: error for not supported devices.

[Sanjuán García, Jorge]

This patch fixes an issue where, if a MEN Chameleon device is not
supported, the early exit in chameleon_parse_gdd() will end up
calling put_device() when no device has been initialized yet. Because
the MCB subsystem does not support all the possible chameleon devices
listed for one FPGA, dmesg gets a few of these when parsing a Chameleon
FPGA:

[   32.974385] No BAR for 16z024
[   32.974386] ------------[ cut here ]------------
[   32.974388] kobject: '(null)' (000000002644a89d): is not initialized, yet kobject_put() is being called.
[   32.974403] WARNING: CPU: 0 PID: 103 at lib/kobject.c:726 kobject_put+0x52/0xa0
[   32.974410] Modules linked in: mcb_pci(+) intel_cstate mcb acpi_pad mac_hid mxm_wmi sch_fq_codel ipmi_devintf ipmi_msghandler msr parport_pc ppdev lp parport pstore_blk drm ramoops pstore_zone efi_pstore reed_solomon ip_tables x_tables autofs4 uas usb_storage spi_intel_platform spi_intel gpio_ich ixgbe igb i2c_i801 xhci_pci i2c_algo_bit xfrm_algo crc32_pclmul e1000e i2c_smbus lpc_ich xhci_pci_renesas dca mdio wmi
[   32.974455] CPU: 0 PID: 103 Comm: kworker/0:3 Tainted: G        W          6.2.0-32-generic #32~22.04.1-Ubuntu
[   32.974458] Hardware name: MEN Mikro Elektronik GmbH G25A/n/a, BIOS 1.01 01/31/2017
[   32.974460] Workqueue: events work_for_cpu_fn
[   32.974467] RIP: 0010:kobject_put+0x52/0xa0
[   32.974472] Code: 74 39 85 c0 7e 4f 4c 8b 65 f8 c9 31 c0 31 d2 31 f6 31 ff c3 cc cc cc cc 48 8b 37 48 89 fa 48 c7 c7 48 69 65 98 e8 2e ae 0e ff <0f> 0b eb be 31 c0 31 d2 31 f6 31 ff c3 cc cc cc cc 4c 89 e7 e8 05
[   32.974475] RSP: 0000:ffff9a0600597d48 EFLAGS: 00010246
[   32.974478] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   32.974480] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[   32.974481] RBP: ffff9a0600597d50 R08: 0000000000000000 R09: 0000000000000000
[   32.974483] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8bab960c3800
[   32.974486] R13: 0000000000000000 R14: 0000000000004000 R15: ffff8bab95895c00
[   32.974488] FS:  0000000000000000(0000) GS:ffff8bb2dfc00000(0000) knlGS:0000000000000000
[   32.974491] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   32.974493] CR2: 00007f7e688fdf3e CR3: 000000011007c003 CR4: 00000000003706f0
[   32.974496] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   32.974498] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   32.974500] Call Trace:
[   32.974501]  <TASK>
[   32.974503]  ? show_regs+0x72/0x90
[   32.974507]  ? kobject_put+0x52/0xa0
[   32.974512]  ? __warn+0x8d/0x160
[   32.974518]  ? kobject_put+0x52/0xa0
[   32.974523]  ? report_bug+0x1bb/0x1d0
[   32.974530]  ? handle_bug+0x46/0x90
[   32.974536]  ? exc_invalid_op+0x19/0x80
[   32.974542]  ? asm_exc_invalid_op+0x1b/0x20
[   32.974547]  ? kobject_put+0x52/0xa0
[   32.974552]  ? kobject_put+0x52/0xa0
[   32.974557]  put_device+0x13/0x30
[   32.974563]  chameleon_parse_gdd+0x149/0x1d0 [mcb]
[   32.974573]  ? chameleon_get_bar+0xc2/0xf0 [mcb]
[   32.974583]  chameleon_parse_cells+0x196/0x1c4 [mcb]
[   32.974593]  mcb_pci_probe+0xf5/0x280 [mcb_pci]
[   32.974602]  local_pci_probe+0x4b/0xb0
[   32.974607]  work_for_cpu_fn+0x1a/0x30
[   32.974613]  process_one_work+0x21f/0x440
[   32.974618]  worker_thread+0x200/0x3f0
[   32.974623]  ? __pfx_worker_thread+0x10/0x10
[   32.974627]  kthread+0xee/0x120
[   32.974633]  ? __pfx_kthread+0x10/0x10
[   32.974639]  ret_from_fork+0x2c/0x50
[   32.974644]  </TASK>
[   32.974646] ---[ end trace 0000000000000000 ]---

This error was introduced in commit: 
   commit 728ac3389296 ("mcb: mcb-parse: fix error handing in chameleon_parse_gdd()")

Jorge Sanjuan Garcia (1):
  mcb: fix error handling for different scenarios when parsing

 drivers/mcb/mcb-core.c  | 1 +
 drivers/mcb/mcb-parse.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

-- 
2.34.1

[RESEND PATCH 1/1] mcb: fix error handling for different scenarios when parsing

[Sanjuán García, Jorge]

chameleon_parse_gdd() may fail for different reasons and end up
in the err tag. Make sure we at least always free the mcb_device
allocated with mcb_alloc_dev().

If mcb_device_register() fails, make sure to give up the reference
in the same place the device was added.

Fixes: 728ac3389296 ("mcb: mcb-parse: fix error handing in chameleon_parse_gdd()")
Reviewed-by: Jose Javier Rodriguez Barbarin <JoseJavier.Rodriguez@duagon.com>
Signed-off-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
---
 drivers/mcb/mcb-core.c  | 1 +
 drivers/mcb/mcb-parse.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mcb/mcb-core.c b/drivers/mcb/mcb-core.c
index 2f23b9c3b751..f797d078978f 100644
--- a/drivers/mcb/mcb-core.c
+++ b/drivers/mcb/mcb-core.c
@@ -247,6 +247,7 @@ int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
 	return 0;
 
 out:
+	put_device(&dev->dev);
 
 	return ret;
 }
diff --git a/drivers/mcb/mcb-parse.c b/drivers/mcb/mcb-parse.c
index 656b6b71c768..1ae37e693de0 100644
--- a/drivers/mcb/mcb-parse.c
+++ b/drivers/mcb/mcb-parse.c
@@ -106,7 +106,7 @@ static int chameleon_parse_gdd(struct mcb_bus *bus,
 	return 0;
 
 err:
-	put_device(&mdev->dev);
+	mcb_free_dev(mdev);
 
 	return ret;
 }
-- 
2.34.1

Re: [RESEND PATCH 1/1] mcb: fix error handling for different scenarios when parsing

[gregkh]

On Thu, Oct 19, 2023 at 02:15:34PM +0000, Sanjuán García, Jorge wrote:
> chameleon_parse_gdd() may fail for different reasons and end up
> in the err tag. Make sure we at least always free the mcb_device
> allocated with mcb_alloc_dev().
> 
> If mcb_device_register() fails, make sure to give up the reference
> in the same place the device was added.
> 
> Fixes: 728ac3389296 ("mcb: mcb-parse: fix error handing in chameleon_parse_gdd()")
> Reviewed-by: Jose Javier Rodriguez Barbarin <JoseJavier.Rodriguez@duagon.com>
> Signed-off-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
> ---
>  drivers/mcb/mcb-core.c  | 1 +
>  drivers/mcb/mcb-parse.c | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mcb/mcb-core.c b/drivers/mcb/mcb-core.c
> index 2f23b9c3b751..f797d078978f 100644
> --- a/drivers/mcb/mcb-core.c
> +++ b/drivers/mcb/mcb-core.c
> @@ -247,6 +247,7 @@ int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
>  	return 0;
>  
>  out:
> +	put_device(&dev->dev);
>  
>  	return ret;
>  }
> diff --git a/drivers/mcb/mcb-parse.c b/drivers/mcb/mcb-parse.c
> index 656b6b71c768..1ae37e693de0 100644
> --- a/drivers/mcb/mcb-parse.c
> +++ b/drivers/mcb/mcb-parse.c
> @@ -106,7 +106,7 @@ static int chameleon_parse_gdd(struct mcb_bus *bus,
>  	return 0;
>  
>  err:
> -	put_device(&mdev->dev);
> +	mcb_free_dev(mdev);
>  
>  	return ret;
>  }
> -- 
> 2.34.1


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