| Message ID | 1397034804-27161-1-git-send-email-helmut.schaa@googlemail.com |
|---|---|
| State | Accepted |
| Commit | 44991b3d19cd71eabe68019ae7cb91df0c929614 |
| Headers | show |
>From: Helmut Schaa [mailto:helmut.schaa@googlemail.com] > >nand_write_subpage_hwecc causes a crash if the driver did not register >ecc->hwctl or ecc->calculate. Fix this by disabling subpage writes if >ecc->hwctl or ecc->calculate is not provided by the driver. > >This behavior was introduced in commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9 >"mtd: nand: subpage write support for hardware based ECC schemes". > >This fixes a crash with fsl_elbc_nand and maybe others: > >Unable to handle kernel paging request for instruction fetch >Faulting instruction address: 0x00000000 >Oops: Kernel access of bad area, sig: 11 [#1] >SMP NR_CPUS=2 P1020 RDB >Modules linked in: ath9k ath9k_common pppoe ppp_async option iptable_nat ath9k_hw ath usb_wwan pppox ppp_generic >nf_nat_ipv4 nf_conntrack_ipv4 mac80211 ipt_MASQUERADE cfg80211 xt_time xt_tcpudp xt_state xt_quota xt_policy xt_pkttype >xt_owner xt_nat xt_multiport xt_mh >CPU: 1 PID: 2161 Comm: ubiformat Not tainted 3.10.26 #6 >task: efbc2700 ti: c7950000 task.ti: c7950000 >NIP: 00000000 LR: c01a495c CTR: 00000000 >REGS: c7951cb0 TRAP: 0400 Not tainted (3.10.26) >MSR: 00029000 <CE,EE,ME> CR: 24002028 XER: 00000000 > >GPR00: c01a4b6c c7951d60 efbc2700 ef84b000 00000001 00000000 000001ff c7800500 >GPR08: 00000000 00000000 efae5e40 c01a4ae4 24002022 10023418 c7951e5c c7800500 >GPR16: c017b6a8 00000000 0000003f c053404c 00000000 00000004 00000000 00000003 >GPR24: 00000010 00000200 ef84b000 c7800d00 c7800000 c7800500 ef84b1c8 00000000 >NIP [00000000] (null) >LR [c01a495c] nand_write_subpage_hwecc+0x74/0x174 >Call Trace: >[c7951d60] [c7951d64] 0xc7951d64 (unreliable) >[c7951da0] [c01a4b6c] nand_write_page+0x88/0x198 >[c7951dd0] [c01a5f7c] nand_do_write_ops+0x2f4/0x39c >[c7951e40] [c01a61e0] nand_write+0x58/0x84 >[c7951e80] [c019e29c] mtdchar_write+0x1dc/0x28c >[c7951ef0] [c00aba84] vfs_write+0xcc/0x1ac >[c7951f10] [c00ac04c] SyS_write+0x4c/0x90 >[c7951f40] [c000cd84] ret_from_syscall+0x0/0x3c > --- Exception: c01 at 0x48050ed8 > LR = 0x100071b8 > Instruction dump: > XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX > XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX > ---[ end trace 161d3c65a2a15cb8 ]--- > >Kernel panic - not syncing: Fatal exception > >Cc: Gupta, Pekon <pekon@ti.com> >Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> >Cc: David Woodhouse <David.Woodhouse@intel.com> >Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com> >--- >I noticed this bug on openwrt with kernel 3.10 but it looks as if this can >still happen in more recent kernels. > > drivers/mtd/nand/nand_base.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > >diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c >index 9715a7b..2298289 100644 >--- a/drivers/mtd/nand/nand_base.c >+++ b/drivers/mtd/nand/nand_base.c >@@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) > ecc->write_oob = nand_write_oob_std; > if (!ecc->read_subpage) > ecc->read_subpage = nand_read_subpage; >- if (!ecc->write_subpage) >+ if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) I don't think this is correct because nand_write_subpage_hwecc() is a replaceable function (default generic implementation). So (1) if chip->ecc.hwctl() and chip->ecc.calculate are not implemented but you still want to use subpage write feature, then you need to provide custom implementation for chip->ecc.write_subpage(). that's same for other interfaces of nand_chip like chip->ecc.write_page(). (2) If you don't want to use subpage write feature then just disable it using chip->options |= NAND_NO_SUBPAGE_WRITE; Can you please tell which NAND controller driver is causing this ? We need to fix that.. with regards, pekon
On Wed, Apr 9, 2014 at 11:38 AM, Gupta, Pekon <pekon@ti.com> wrote: >>diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c >>index 9715a7b..2298289 100644 >>--- a/drivers/mtd/nand/nand_base.c >>+++ b/drivers/mtd/nand/nand_base.c >>@@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) >> ecc->write_oob = nand_write_oob_std; >> if (!ecc->read_subpage) >> ecc->read_subpage = nand_read_subpage; >>- if (!ecc->write_subpage) >>+ if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) > > I don't think this is correct because nand_write_subpage_hwecc() is a > replaceable function (default generic implementation). So > > (1) if chip->ecc.hwctl() and chip->ecc.calculate are not implemented but you > still want to use subpage write feature, then you need to provide custom > implementation for chip->ecc.write_subpage(). > that's same for other interfaces of nand_chip like chip->ecc.write_page(). But these don't cause panics :) > (2) If you don't want to use subpage write feature then just disable it using > chip->options |= NAND_NO_SUBPAGE_WRITE; > > Can you please tell which NAND controller driver is causing this ? > We need to fix that.. This happens with fsl_elbc_nand (while trying to run ubiformat on a mtd dev) but the crash was caused by the introduction of nand_write_subpage_hwecc. So, in this case I think instead of trying to fix every possible driver we should let the nand core code handle this issue gracefully. Maybe we could add a WARN_ON_ONCE to notice which drivers require adjustments. Regards, Helmut
Hi, I have my archaeology hat on, in the deep corners of my mailbox... On Wed, Apr 09, 2014 at 11:13:24AM +0200, Helmut Schaa wrote: > nand_write_subpage_hwecc causes a crash if the driver did not register > ecc->hwctl or ecc->calculate. Fix this by disabling subpage writes if > ecc->hwctl or ecc->calculate is not provided by the driver. > > This behavior was introduced in commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9 > "mtd: nand: subpage write support for hardware based ECC schemes". > > This fixes a crash with fsl_elbc_nand and maybe others: > [...] > > Cc: Gupta, Pekon <pekon@ti.com> > Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> > Cc: David Woodhouse <David.Woodhouse@intel.com> > Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com> > --- > I noticed this bug on openwrt with kernel 3.10 but it looks as if this can > still happen in more recent kernels. > > drivers/mtd/nand/nand_base.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index 9715a7b..2298289 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) > ecc->write_oob = nand_write_oob_std; > if (!ecc->read_subpage) > ecc->read_subpage = nand_read_subpage; > - if (!ecc->write_subpage) > + if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) > ecc->write_subpage = nand_write_subpage_hwecc; > > case NAND_ECC_HW_SYNDROME: I realize we've merged a fix for fsl_elbc_nand long ago (commit f034d87def51 "mtd: eLBC NAND: fix subpage write support"), but this change still looks sane, applies, and could possibly fix some other drivers that are lurking somewhere. Any reason I shouldn't apply it? Regards, Brian
On Thu, Dec 10, 2015 at 12:58 AM, Brian Norris <computersforpeace@gmail.com> wrote: > Hi, > > I have my archaeology hat on, in the deep corners of my mailbox... > > On Wed, Apr 09, 2014 at 11:13:24AM +0200, Helmut Schaa wrote: >> nand_write_subpage_hwecc causes a crash if the driver did not register >> ecc->hwctl or ecc->calculate. Fix this by disabling subpage writes if >> ecc->hwctl or ecc->calculate is not provided by the driver. >> >> This behavior was introduced in commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9 >> "mtd: nand: subpage write support for hardware based ECC schemes". >> >> This fixes a crash with fsl_elbc_nand and maybe others: >> > [...] >> >> Cc: Gupta, Pekon <pekon@ti.com> >> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> >> Cc: David Woodhouse <David.Woodhouse@intel.com> >> Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com> >> --- >> I noticed this bug on openwrt with kernel 3.10 but it looks as if this can >> still happen in more recent kernels. >> >> drivers/mtd/nand/nand_base.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c >> index 9715a7b..2298289 100644 >> --- a/drivers/mtd/nand/nand_base.c >> +++ b/drivers/mtd/nand/nand_base.c >> @@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) >> ecc->write_oob = nand_write_oob_std; >> if (!ecc->read_subpage) >> ecc->read_subpage = nand_read_subpage; >> - if (!ecc->write_subpage) >> + if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) >> ecc->write_subpage = nand_write_subpage_hwecc; >> >> case NAND_ECC_HW_SYNDROME: > > I realize we've merged a fix for fsl_elbc_nand long ago (commit > f034d87def51 "mtd: eLBC NAND: fix subpage write support"), but this > change still looks sane, applies, and could possibly fix some other > drivers that are lurking somewhere. Any reason I shouldn't apply it? I'm not carrying this patch in my tree anymore and did not see any more crashes with the flash configuration I'm using. So, I think the original patch is kind of superfluous. Regards, Helmut
On Thu, Dec 10, 2015 at 10:31:32AM +0100, Helmut Schaa wrote: > On Thu, Dec 10, 2015 at 12:58 AM, Brian Norris > <computersforpeace@gmail.com> wrote: > > On Wed, Apr 09, 2014 at 11:13:24AM +0200, Helmut Schaa wrote: > >> nand_write_subpage_hwecc causes a crash if the driver did not register > >> ecc->hwctl or ecc->calculate. Fix this by disabling subpage writes if > >> ecc->hwctl or ecc->calculate is not provided by the driver. > >> > >> This behavior was introduced in commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9 > >> "mtd: nand: subpage write support for hardware based ECC schemes". > >> > >> This fixes a crash with fsl_elbc_nand and maybe others: > >> > > [...] > >> > >> --- a/drivers/mtd/nand/nand_base.c > >> +++ b/drivers/mtd/nand/nand_base.c > >> @@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) > >> ecc->write_oob = nand_write_oob_std; > >> if (!ecc->read_subpage) > >> ecc->read_subpage = nand_read_subpage; > >> - if (!ecc->write_subpage) > >> + if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) > >> ecc->write_subpage = nand_write_subpage_hwecc; > >> > >> case NAND_ECC_HW_SYNDROME: > > > > I realize we've merged a fix for fsl_elbc_nand long ago (commit > > f034d87def51 "mtd: eLBC NAND: fix subpage write support"), but this > > change still looks sane, applies, and could possibly fix some other > > drivers that are lurking somewhere. Any reason I shouldn't apply it? > > I'm not carrying this patch in my tree anymore and did not see any more > crashes with the flash configuration I'm using. So, I think the original patch > is kind of superfluous. There could easily be other drivers that don't have hwctl() or calculate() callbacks yet use NAND_ECC_HW. By inspection, I see that maybe the new hisi504_nand.c is susceptible, as well as sh_flctl.c and maybe even sunxi_nand.c (?). Some of these might not be hit if they don't use NAND that support subpage writes. Anyway, I think this patch is helpful, because it prevents drivers from having to fill in a 'subpage' write callback that looks just like their write_page() callback. Brian
Hi Brian, On Fri, 11 Dec 2015 16:40:25 -0800 Brian Norris <computersforpeace@gmail.com> wrote: > On Thu, Dec 10, 2015 at 10:31:32AM +0100, Helmut Schaa wrote: > > On Thu, Dec 10, 2015 at 12:58 AM, Brian Norris > > <computersforpeace@gmail.com> wrote: > > > On Wed, Apr 09, 2014 at 11:13:24AM +0200, Helmut Schaa wrote: > > >> nand_write_subpage_hwecc causes a crash if the driver did not register > > >> ecc->hwctl or ecc->calculate. Fix this by disabling subpage writes if > > >> ecc->hwctl or ecc->calculate is not provided by the driver. > > >> > > >> This behavior was introduced in commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9 > > >> "mtd: nand: subpage write support for hardware based ECC schemes". > > >> > > >> This fixes a crash with fsl_elbc_nand and maybe others: > > >> > > > [...] > > >> > > >> --- a/drivers/mtd/nand/nand_base.c > > >> +++ b/drivers/mtd/nand/nand_base.c > > >> @@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) > > >> ecc->write_oob = nand_write_oob_std; > > >> if (!ecc->read_subpage) > > >> ecc->read_subpage = nand_read_subpage; Shouldn't we have the same kind of test for ->read_subpage. if (!ecc->read_subpage && ecc->correct && ecc->calculate) ecc->read_subpage = nand_read_subpage; > > >> - if (!ecc->write_subpage) > > >> + if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) > > >> ecc->write_subpage = nand_write_subpage_hwecc; > > >> > > >> case NAND_ECC_HW_SYNDROME: > > > > > > I realize we've merged a fix for fsl_elbc_nand long ago (commit > > > f034d87def51 "mtd: eLBC NAND: fix subpage write support"), but this > > > change still looks sane, applies, and could possibly fix some other > > > drivers that are lurking somewhere. Any reason I shouldn't apply it? > > > > I'm not carrying this patch in my tree anymore and did not see any more > > crashes with the flash configuration I'm using. So, I think the original patch > > is kind of superfluous. > > There could easily be other drivers that don't have hwctl() or > calculate() callbacks yet use NAND_ECC_HW. By inspection, I see that > maybe the new hisi504_nand.c is susceptible, as well as sh_flctl.c and > maybe even sunxi_nand.c (?). Some of these might not be hit if they > don't use NAND that support subpage writes. Yep, sunxi platforms could be hit by this bug, but it seems nobody decided to design a board with an SLC NAND (and MLCs are not supporting subpage writes). > > Anyway, I think this patch is helpful, because it prevents drivers from > having to fill in a 'subpage' write callback that looks just like their > write_page() callback. I agree. Best Regards, Boris
On Sat, Dec 12, 2015 at 8:59 AM, Boris Brezillon <boris.brezillon@free-electrons.com> wrote: > Hi Brian, > > On Fri, 11 Dec 2015 16:40:25 -0800 > Brian Norris <computersforpeace@gmail.com> wrote: > >> On Thu, Dec 10, 2015 at 10:31:32AM +0100, Helmut Schaa wrote: >> > On Thu, Dec 10, 2015 at 12:58 AM, Brian Norris >> > <computersforpeace@gmail.com> wrote: >> > > On Wed, Apr 09, 2014 at 11:13:24AM +0200, Helmut Schaa wrote: >> > >> nand_write_subpage_hwecc causes a crash if the driver did not register >> > >> ecc->hwctl or ecc->calculate. Fix this by disabling subpage writes if >> > >> ecc->hwctl or ecc->calculate is not provided by the driver. >> > >> >> > >> This behavior was introduced in commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9 >> > >> "mtd: nand: subpage write support for hardware based ECC schemes". >> > >> >> > >> This fixes a crash with fsl_elbc_nand and maybe others: >> > >> >> > > [...] >> > >> >> > >> --- a/drivers/mtd/nand/nand_base.c >> > >> +++ b/drivers/mtd/nand/nand_base.c >> > >> @@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) >> > >> ecc->write_oob = nand_write_oob_std; >> > >> if (!ecc->read_subpage) >> > >> ecc->read_subpage = nand_read_subpage; > > Shouldn't we have the same kind of test for ->read_subpage. > > if (!ecc->read_subpage && ecc->correct && > ecc->calculate) > ecc->read_subpage = nand_read_subpage; > > >> > >> - if (!ecc->write_subpage) >> > >> + if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) >> > >> ecc->write_subpage = nand_write_subpage_hwecc; >> > >> >> > >> case NAND_ECC_HW_SYNDROME: >> > > >> > > I realize we've merged a fix for fsl_elbc_nand long ago (commit >> > > f034d87def51 "mtd: eLBC NAND: fix subpage write support"), but this >> > > change still looks sane, applies, and could possibly fix some other >> > > drivers that are lurking somewhere. Any reason I shouldn't apply it? >> > >> > I'm not carrying this patch in my tree anymore and did not see any more >> > crashes with the flash configuration I'm using. So, I think the original patch >> > is kind of superfluous. >> >> There could easily be other drivers that don't have hwctl() or >> calculate() callbacks yet use NAND_ECC_HW. By inspection, I see that >> maybe the new hisi504_nand.c is susceptible, as well as sh_flctl.c and >> maybe even sunxi_nand.c (?). Some of these might not be hit if they >> don't use NAND that support subpage writes. > > Yep, sunxi platforms could be hit by this bug, but it seems nobody > decided to design a board with an SLC NAND (and MLCs are not supporting > subpage writes). > >> >> Anyway, I think this patch is helpful, because it prevents drivers from >> having to fill in a 'subpage' write callback that looks just like their >> write_page() callback. > > I agree. Fine with me then. Helmut
On Sat, Dec 12, 2015 at 08:59:00AM +0100, Boris Brezillon wrote: > On Fri, 11 Dec 2015 16:40:25 -0800 > Brian Norris <computersforpeace@gmail.com> wrote: > > > On Thu, Dec 10, 2015 at 10:31:32AM +0100, Helmut Schaa wrote: > > > On Thu, Dec 10, 2015 at 12:58 AM, Brian Norris > > > <computersforpeace@gmail.com> wrote: > > > > On Wed, Apr 09, 2014 at 11:13:24AM +0200, Helmut Schaa wrote: > > > >> nand_write_subpage_hwecc causes a crash if the driver did not register > > > >> ecc->hwctl or ecc->calculate. Fix this by disabling subpage writes if > > > >> ecc->hwctl or ecc->calculate is not provided by the driver. > > > >> > > > >> This behavior was introduced in commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9 > > > >> "mtd: nand: subpage write support for hardware based ECC schemes". > > > >> > > > >> This fixes a crash with fsl_elbc_nand and maybe others: > > > >> > > > > [...] > > > >> > > > >> --- a/drivers/mtd/nand/nand_base.c > > > >> +++ b/drivers/mtd/nand/nand_base.c > > > >> @@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) > > > >> ecc->write_oob = nand_write_oob_std; > > > >> if (!ecc->read_subpage) > > > >> ecc->read_subpage = nand_read_subpage; > > Shouldn't we have the same kind of test for ->read_subpage. > > if (!ecc->read_subpage && ecc->correct && > ecc->calculate) > ecc->read_subpage = nand_read_subpage; We could do that, though right now we have a little less danger for read_subpage() than we do with write_subpage(), because drivers have to opt in with the NAND_SUBPAGE_READ flag before this function will actually be used. Feel free to send a patch if you'd like. > > > >> - if (!ecc->write_subpage) > > > >> + if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) > > > >> ecc->write_subpage = nand_write_subpage_hwecc; > > > >> > > > >> case NAND_ECC_HW_SYNDROME: > > > > > > > > I realize we've merged a fix for fsl_elbc_nand long ago (commit > > > > f034d87def51 "mtd: eLBC NAND: fix subpage write support"), but this > > > > change still looks sane, applies, and could possibly fix some other > > > > drivers that are lurking somewhere. Any reason I shouldn't apply it? > > > > > > I'm not carrying this patch in my tree anymore and did not see any more > > > crashes with the flash configuration I'm using. So, I think the original patch > > > is kind of superfluous. > > > > There could easily be other drivers that don't have hwctl() or > > calculate() callbacks yet use NAND_ECC_HW. By inspection, I see that > > maybe the new hisi504_nand.c is susceptible, as well as sh_flctl.c and > > maybe even sunxi_nand.c (?). Some of these might not be hit if they > > don't use NAND that support subpage writes. > > Yep, sunxi platforms could be hit by this bug, but it seems nobody > decided to design a board with an SLC NAND (and MLCs are not supporting > subpage writes). > > > > > Anyway, I think this patch is helpful, because it prevents drivers from > > having to fill in a 'subpage' write callback that looks just like their > > write_page() callback. > > I agree. OK. Applied to l2-mtd.git, with additional commentary about how the reported issue is already fixed, but there could be other drivers who run across this problem. Brian
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 9715a7b..2298289 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -3768,7 +3768,7 @@ int nand_scan_tail(struct mtd_info *mtd) ecc->write_oob = nand_write_oob_std; if (!ecc->read_subpage) ecc->read_subpage = nand_read_subpage; - if (!ecc->write_subpage) + if (!ecc->write_subpage && ecc->hwctl && ecc->calculate) ecc->write_subpage = nand_write_subpage_hwecc; case NAND_ECC_HW_SYNDROME:
nand_write_subpage_hwecc causes a crash if the driver did not register ecc->hwctl or ecc->calculate. Fix this by disabling subpage writes if ecc->hwctl or ecc->calculate is not provided by the driver. This behavior was introduced in commit 837a6ba4f3b6d23026674e6af6b6849a4634fff9 "mtd: nand: subpage write support for hardware based ECC schemes". This fixes a crash with fsl_elbc_nand and maybe others: Unable to handle kernel paging request for instruction fetch Faulting instruction address: 0x00000000 Oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=2 P1020 RDB Modules linked in: ath9k ath9k_common pppoe ppp_async option iptable_nat ath9k_hw ath usb_wwan pppox ppp_generic nf_nat_ipv4 nf_conntrack_ipv4 mac80211 ipt_MASQUERADE cfg80211 xt_time xt_tcpudp xt_state xt_quota xt_policy xt_pkttype xt_owner xt_nat xt_multiport xt_mh CPU: 1 PID: 2161 Comm: ubiformat Not tainted 3.10.26 #6 task: efbc2700 ti: c7950000 task.ti: c7950000 NIP: 00000000 LR: c01a495c CTR: 00000000 REGS: c7951cb0 TRAP: 0400 Not tainted (3.10.26) MSR: 00029000 <CE,EE,ME> CR: 24002028 XER: 00000000 GPR00: c01a4b6c c7951d60 efbc2700 ef84b000 00000001 00000000 000001ff c7800500 GPR08: 00000000 00000000 efae5e40 c01a4ae4 24002022 10023418 c7951e5c c7800500 GPR16: c017b6a8 00000000 0000003f c053404c 00000000 00000004 00000000 00000003 GPR24: 00000010 00000200 ef84b000 c7800d00 c7800000 c7800500 ef84b1c8 00000000 NIP [00000000] (null) LR [c01a495c] nand_write_subpage_hwecc+0x74/0x174 Call Trace: [c7951d60] [c7951d64] 0xc7951d64 (unreliable) [c7951da0] [c01a4b6c] nand_write_page+0x88/0x198 [c7951dd0] [c01a5f7c] nand_do_write_ops+0x2f4/0x39c [c7951e40] [c01a61e0] nand_write+0x58/0x84 [c7951e80] [c019e29c] mtdchar_write+0x1dc/0x28c [c7951ef0] [c00aba84] vfs_write+0xcc/0x1ac [c7951f10] [c00ac04c] SyS_write+0x4c/0x90 [c7951f40] [c000cd84] ret_from_syscall+0x0/0x3c --- Exception: c01 at 0x48050ed8 LR = 0x100071b8 Instruction dump: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX ---[ end trace 161d3c65a2a15cb8 ]--- Kernel panic - not syncing: Fatal exception Cc: Gupta, Pekon <pekon@ti.com> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com> --- I noticed this bug on openwrt with kernel 3.10 but it looks as if this can still happen in more recent kernels. drivers/mtd/nand/nand_base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)