Currently add_mtd_device() failures are plainly ignored, which may lead
to kernel crashes later.
E.g. after flipping SW17 on r8a7791/koelsch, to switch from the large to
the small QSPI FLASH, without updating the partition description in DT,
the following happens:
m25p80 spi0.0: found s25sl032p, expected s25fl512s
3 fixed-partitions partitions found on MTD device spi0.0
Creating 3 MTD partitions on "spi0.0":
0x000000000000-0x000000080000 : "loader"
0x000000080000-0x000000600000 : "user"
mtd: partition "user" extends beyond the end of device "spi0.0" -- size truncated to 0x380000
The second partition is truncated correctly.
0x000000600000-0x000004000000 : "flash"
mtd: partition "flash" is out of reach -- disabled
The third partition is disabled by allocate_partition(), which means
fields like erasesize are not filled in. Hence add_mtd_device() fails
and screams, rightfully:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 1 at drivers/mtd/mtdcore.c:508 add_mtd_device+0x2a0/0x2e0
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.16.0-koelsch-08649-g58e35e77b00c075d #4029
Hardware name: Generic R-Car Gen2 (Flattened Device Tree)
[<c020f660>] (unwind_backtrace) from [<c020b2f4>] (show_stack+0x10/0x14)
[<c020b2f4>] (show_stack) from [<c076d088>] (dump_stack+0x7c/0x9c)
[<c076d088>] (dump_stack) from [<c02210d8>] (__warn+0xd4/0x104)
[<c02210d8>] (__warn) from [<c0221218>] (warn_slowpath_null+0x38/0x44)
[<c0221218>] (warn_slowpath_null) from [<c0553db4>] (add_mtd_device+0x2a0/0x2e0)
[<c0553db4>] (add_mtd_device) from [<c0556a70>] (add_mtd_partitions+0xd0/0x16c)
[<c0556a70>] (add_mtd_partitions) from [<c0553f88>] (mtd_device_parse_register+0xc4/0x1b4)
[<c0553f88>] (mtd_device_parse_register) from [<c055a97c>] (m25p_probe+0x148/0x188)
[<c055a97c>] (m25p_probe) from [<c055e278>] (spi_drv_probe+0x84/0xa0)
[...]
---[ end trace d43ce221bca7ab5c ]---
However, that failure is ignored by add_mtd_partitions(), leading to a
crash later:
------------[ cut here ]------------
kernel BUG at fs/sysfs/file.c:330!
Internal error: Oops - BUG: 0 [#1] SMP ARM
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 4.16.0-koelsch-08649-g58e35e77b00c075d #4029
Hardware name: Generic R-Car Gen2 (Flattened Device Tree)
PC is at sysfs_create_file_ns+0x24/0x40
LR is at 0x1
pc : [<c03604cc>] lr : [<00000001>] psr: 60000013
sp : eb447c00 ip : 00000000 fp : c0e20174
r10: 00000003 r9 : c0e20150 r8 : eb7e3818
r7 : ea8b20f8 r6 : c0e2017c r5 : 00000000 r4 : 00000000
r3 : 00000200 r2 : 00000000 r1 : c0e2019c r0 : 00000000
Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 30c5387d Table: 40003000 DAC: 55555555
Process swapper/0 (pid: 1, stack limit = 0x7eba272f)
Stack: (0xeb447c00 to 0xeb448000)
[...]
[<c03604cc>] (sysfs_create_file_ns) from [<c036051c>] (sysfs_create_files+0x34/0x70)
[<c036051c>] (sysfs_create_files) from [<c0556288>] (mtd_add_partition_attrs+0x10/0x34)
[<c0556288>] (mtd_add_partition_attrs) from [<c0556a78>] (add_mtd_partitions+0xd8/0x16c)
[<c0556a78>] (add_mtd_partitions) from [<c0553f88>] (mtd_device_parse_register+0xc4/0x1b4)
[<c0553f88>] (mtd_device_parse_register) from [<c055a97c>] (m25p_probe+0x148/0x188)
[<c055a97c>] (m25p_probe) from [<c055e278>] (spi_drv_probe+0x84/0xa0)
Fix this by ignoring and freeing partitions that failed to add in
add_mtd_partitions(). The same issue is present in mtd_add_partition(),
so fix that as well.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
I don't know if it is worthwhile factoring out the common handling.
Should allocate_partition() fail instead? There's a comment saying
"let's register it anyway to preserve ordering".
---
drivers/mtd/mtdpart.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 023516a632766c42..d41adc1397dcf95e 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -637,7 +637,14 @@ int mtd_add_partition(struct mtd_info *parent, const char *name,
list_add(&new->list, &mtd_partitions);
mutex_unlock(&mtd_partitions_mutex);
- add_mtd_device(&new->mtd);
+ ret = add_mtd_device(&new->mtd);
+ if (ret) {
+ mutex_lock(&mtd_partitions_mutex);
+ list_del(&new->list);
+ mutex_unlock(&mtd_partitions_mutex);
+ free_partition(new);
+ return ret;
+ }
mtd_add_partition_attrs(new);
@@ -731,7 +738,7 @@ int add_mtd_partitions(struct mtd_info *master,
{
struct mtd_part *slave;
uint64_t cur_offset = 0;
- int i;
+ int i, ret;
printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);
@@ -746,7 +753,15 @@ int add_mtd_partitions(struct mtd_info *master,
list_add(&slave->list, &mtd_partitions);
mutex_unlock(&mtd_partitions_mutex);
- add_mtd_device(&slave->mtd);
+ ret = add_mtd_device(&slave->mtd);
+ if (ret) {
+ mutex_lock(&mtd_partitions_mutex);
+ list_del(&slave->list);
+ mutex_unlock(&mtd_partitions_mutex);
+ free_partition(slave);
+ continue;
+ }
+
mtd_add_partition_attrs(slave);
if (parts[i].types)
mtd_parse_part(slave, parts[i].types);
--
2.7.4
